Micaceous Sandstone Research Articles

Coal Resources of Part of Southern Illinois Basin: ABSTRACT

Pennsylvanian rocks in the southern Illinois basin are sandstone, shale, coal, and thin discontinuous beds of limestone. Stratigraphically these rocks and their associated coal seams have been designated: Caseyville Group, Mt. Rorah and Wise Ridge coals; Tradewater Group, Davis and Dekoven coals; Carbondale Group, #2, #2A, #3, #4, #5, #5A, and #6 coals. The Wise Ridge, Davis, Dekoven, #5, and #6 coals have been strip mined, and the #5 and #6 coals have been deep mined. Extensive subsurface reserves have been proven for the Davis, Dekoven, and #5 coal and strippable reserves for the #5. The Pennsylvanian sediments dip to the north and northwest at 80 to 100 ft/mi. Rocks of the Tradewater Group have been faulted against Upper Mississippian sediments along the Shawneetown-Rough Creek fault, whose displacement is about 1,400 ft (420 m). The upthrown block forms a broad curving ridge with a steep fault-line scarp on the north and this ridge is the dominant topographic feature of the area. The Cottage Grove fault trends slightly north of west across the northern boundary of the area and has a displacement up to 150 ft (45 m). No structural features have been discovered on the east and west sides of the area. The sediments between the coals generally consist of, End_Page 503------------------------------ from bottom to top: black carbonaceous fossiliferous shale; gray shale locally fossiliferous; gray shale; cross-bedded micaceous sandstone which is interlaminated and interbedded at the bottom with shale. These rocks are believed to represent marine-lagoonal, tidal-flat, distributary-channel, or channel environments, respectively. End_of_Article - Last_Page 504------------

Formation Permeability Damage by Mica Alteration and Carbonate Dissolution

Two formation damage mechanisms that can cause severe permeability damage in friable micaceous sandstones during flow of neutral salt solutions are described. Laboratory flow studies on cores suggest that damage by these mechanisms is probably quite common and should be considered in all poorly, consolidated micaceous sands. Introduction Permeability damage mechanisms involving clay Permeability damage mechanisms involving clay structural expansion and particle dispersion have been discussed previously. It has been shown that permeability damage by aqueous solutions usually can be permeability damage by aqueous solutions usually can be prevented in even very clayey sands by maintaining some prevented in even very clayey sands by maintaining some minimum amount of dissolved salt in the flowing solution. Gray and Rex showed that even distilled water can be flowed without significant damage if the clays previously are saturated with calcium ions. Over the years, I have observed that some reservoir sands tend to lose permeability in laboratory flow studies during flow of salt solutions that normally prevent clay damage problems. This usually occurred in relatively recent sediments and most were fairly friable. The layered minerals in these young sediments are predominately mica with lesser amounts of montmorillonite, predominately mica with lesser amounts of montmorillonite, kaolinite and chlorite. Several authors have reported on the mechanism of potassium release by micaceous minerals and the effects of potassium extract on the properties of mica. Based on these reports and recent properties of mica. Based on these reports and recent laboratory studies, I propose two mechanisms to account for at least some of the permeability damage observed in such friable micaceous sands. The objectives of this paper are to describe the proposed damage mechanisms and to present laboratory and proposed damage mechanisms and to present laboratory and field data supporting them. Materials and Methods Reservoir sandstone samples from several Southern California oil fields were used in the study. The sands were chosen on the basis of their mica content, friability, and observed permeability damage from flowing salt solutions. The mineralogical composition of single samples of reservoir sand from the five oil fields included in the study are shown in Table 1. The compositions as determined by X-ray diffraction are typical for Los Angeles Basin Miocene sands. Small cores about 1/2 in. square and 1 to 2 in. long were cut from full-bore rubbersleeve and conventional cores. The sands were poorly consolidated, which necessitated hand carving the small cores to the desired size and shape. Fluid flow measurement were made with a permeameter having a constant-rate pump that pumps a permeameter having a constant-rate pump that pumps a driving fluid into a bladder-type accumulator, displacing the test fluid at a constant rate. The test fluid was forced through corns and the differential pressure across each core was measured continuously with a differentialpressure transducer and recorded on a strip-chart recorder. The cores, which had been potted previously in aluminum sleeves with epoxy resin, were confined in a core holder consisting of two end plates secured with through-bolts. All solutions were filtered previously with 0.22-micrometer Millipore filters. Permeabilities were calculated from core dimensions, fluid viscosity, and differential pressure. Carbonate contents of effluents and sands were determined by titrating with hydrochloric acid. In the case of aqueous effluent solutions, a known volume of solution was titrated with 0.01-normal hydrochloric acid to below pH 7. A glass electrode and pH meter were used to pH 7. A glass electrode and pH meter were used to determine pH values. JPT P. 1056

Trace Fossils from the Permo-Triassic of Arran

Synopsis The first identifiable trace fossils recorded in the Permo-Triassic of Arran come from an exposure within the Auchenhew Beds near King’s Cave on the west coast. The forms cf. “Siphonites”, cf. Cylindricum and epichnial burrows, preserved in micaceous sandstones and mudstones, indicate the activity of an ephemeral invertebrate, probably arthropod, fauna in a shallow fluvial-lacustrine environment of unknown salinity. These trace fossil bearing sediments occur in a regional sequence of facies indicating an upwards change in environment from fluvial through aeolian and fluvial-lacustrine to marine.

Trace Fossils in the Lower Tal Formation of Mussoorie and their Environmental Significance

ABSTRACT In the course of lithological mapping of the Krol-Tal succession near Mussoorie in Garhwal Himalaya, a variety of trace fossils have been recorded, occurring as ridge like epireliefs in the Lower Tal micaceous sandstones. So far, only two variety of trails have been identified, both belonging to ichnogenus Aulichnites. A comprehensive study of lithological variations, sedimentary structures, fossils, and close association with shallow-water marine phosphorites in the area, together with the distribution of trace fossils vis-a-vis the types of sandstone has given an indication of depositional conditions prevailing at the time of deposition of Lower Tal sediments.

Natural and Experimental Microstructures in Deformed Micaceous Sandstones

Microscopic features associated with cleavage in micaceous sandstone, siltstone, and silly slate include mica films, mica beards, homogeneous distribution of oriented mica, and equant or inequant quartz. These features occur in rocks in a wide variety of combinations. In experiments, somewhat similar microstructures are obtained by slow folding of wet, salt-mica specimens. Points of resemblance between the artificial cleavage and natural examples are the presence of mica films, the axial-plane orientation of the cleavage, convergent and divergent cleavage fans, refraction of cleavage across lithological boundaries, evidence of possible solution effects, and total strains that are broadly similar in magnitude and orientation to strains estimated in rocks with slaty cleavage.

Tektites: A post-Apollo view

Prior to the receipt of the lunar samples, it was the scientific consensus that tektites were melted and splashed material formed during large cometary or meteorite impact events. Whether the impact took place on the Earth or the Moon was the topic of a long-standing scientific debate, which raged with particular intensity during the decade previous to the lunar landings. Four definite and separate tektite-strewn fields are known: bediasites (North America, 34 m.y.); moldavites (Czechoslovakia, 14 m.y.); Ivory Coast (1.3 m.y.); and Southeast Asian and Australian fields (0.7 m.y.). A fifth possible occurrence, of high-Na australites, possibly 3–4 m.y. old, remains to be substantiated. The age of infall of the australites is not agreed upon. Radiometric and fission track dates agree with the magnetic stratigraphy for deep-sea core microtektite occurrences at about 0.7 m.y. Terrestrial stratigraphic evidence favours a recent (30,000 years) date. The chemistry of tektites appears to reflect that of the parent material, and losses during fusion appear to be restricted to elements and compounds more volatile than cesium. Terrestrial impact glasses provide small-scale analogues of tektite-forming events, and indicate that only the most volatile components are lost during fusion. The Apollo lunar missions provide critical evidence which refutes the hypothesis of lunar origin of tektites. Tektite chemistry is totally distinct from that observed in lunar maria basalts. These possess Cr contents which are two orders of magnitude higher than tektites, distinctive REE patterns with large Eu depletions, high Fe and low SiO 2 contents, low K/U ratios and many other diagnostic features, none of which are observed in the chemistry of tektites. The lunar uplands compositions, as shown by Apollo 14, 15 and 16 samples and the μ-ray and XRF orbiter data, are high-Al, low-SiO 2 compositions totally dissimilar to those of tektites. The composition of lunar rock 12013 shows typical lunar features and is distinct from that of tektites. The small amounts of lunar K-rich granitic material found in the soils have K/Mg and K/Na ratios 10–50 times those of tektites. The ages of the lunar maria (3.2–3.8 aeons) and uplands (> 4.0 aeons) are an order of magnitude older than the parent material of the Southeast Asian and Australian tektites, which yield Rb-Sr isochrons indicating ages of the order of 100–300 m.y. The lunar lead isotopic compositions are highly radiogenic whereas tektites have terrestrial Pb isotopic ratios. Lunar δ 18 O values are low (< 7 per mil) compared with values of +9.6 to +11.5 per mil for tektites. In summary, a lunar impact origin for tektites is not compatible with the chemistry, age or isotopic composition of the lunar samples. A lunar volcanic origin, recently revived by O'Keefe (1970) encounters most of the same problems. Recent lunar volcanism (< 50 m.y.), if the source of tektites, should contribute tektite glass to the upper layers of the regolith. None has been found. The presence of meteoritic components in tektites, and the high pressure phase coesite, are more readily interpreted as evidence of impact. The element abundances and inter-element variations in tektites do not resemble those in terrestrial igneous rocks, but show a close similarity to terrestrial sandstones. The composition of the Southeast Asian tektites, australites and moldavites resembles that of micaceous sandstones or subgreywackes, the Ivory Coast tektite composition is similar to that of greywacke, and the bediasite chemistry is analogous to that of arkose. No suitable terrestrial impact site has been identified for the bediasites, Southeast Asian tektites and australites. It is suggested that a search for the source of these latter strewnfields be made using satellite photographs to look for wide shallow craters produced by super-Tunguska type events on areas of Mesozoic sandstones. The moldavites were possibly formed during the Ries Crater event but, if so, the precise source of the material remains to be identified. The Ivory Coast tektites are linked by chemistry, isotope and age evidence to the Bosumtwi Crater, Ghana. The overall evidence now supports the origin of tektites by cometary (or meteorite) impact on terrestrial sedimentary rocks.

The Røde Ø Conglomerate of inner Scoresby Sund and the Carboniferous(?) and Permian rocks west of the Schuchert Flod. A general sedimentological account

The Røde Ø Conglomerate is a formation of red sandstones and conglomerates in the inner part of Scoresby Sund. It has an elongated north-south outcrop within an area of high-grade metamorphic rocks. It is bounded on the west by a normal fault, downthrowing to the east and dying out northwards. The sediments rest unconformably on migmatites along their eastern boundary. Within the Røde Ø Conglomerate, four lithofacies associations are recognised. A conglomerate association is the most abundant and occurs along the western side of the outcrop against the fault. It is coarse and poorly sorted, and easterly palaeocurrents are suggested. The association is interpreted as the product of alluvial fans building eastwards. This association passes laterally eastwards through an interbedded complex into a silty sandstone association which, in turn, passes into a gypsiferous sandstone association. These are both thought to be largely suspension deposits at the distal limit of the fans. The gypsum is the result of near surface precipitation due to high evaporation. On Storø, on the eastern side of Rødefjord and east of the other associations, a cross-bedded sandstone association referable to a normal fluviatile model occurs. Palaeocurrents here were to the north and north-west. It is suggested that movements along the western boundary fault were probably the cause of the rapid uplift needed to supply the coarse sediment. The rocks west of the Schuchert Flod were described by Kempter (1961) who recognised three major subdivisions, the Bjørnbos Corner Formation of alleged Carboniferous age, the Gurreholmsdal Formation (Lower Permian) and the Karstryggen Group (Upper Permian). The Bjørnbos Corner Formation is an arkosic conglomerate whose sedimentation is not obviously related to any presently observed tectonic feature. The Gurreholmsdal Formation shows a pattern of sedimentation broadly similar to the Røde ø Conglomerate with conglomerates in the west, near the Stauning Alper Fault passing eastwards and downcurrent into finer arkoses and eventually into micaceous sandstones which have northerly palaeocurrents. Sediment supply is again thought to have been due to movement on the western fault margin. It is not possible to date the Røde Ø Conglomerate by comparison with the Schuchert sequence in any conclusive way, though it can be tentatively suggested that the same regional tensional event might have been responsible for both sedimentary events.

Notes on Greenland trace fossils

Freshwater Cruziana from the Upper Triassic of Jameson Land, East Greenland.An occurrence of well-preserved Cruziana problematica (Schindewolf) in Triassic red-beds in Jameson Land allows a more detailed morphological description of these trace fossils than has hitherto been possible. Rheotactic orientation of the traces indicates the direction of palaeocurrents in the area. C. problematica has previously been ascribed to branchiopod crustaceans, but the present material allows a narrowing of the field to Notostraca, and is supported by field observations of the living notostracan Lepidurus arcticus (Pallas).The burrows and microcoprolites of Glyphea rosenkrantzi, a Lower Jurassic palinuran crustacean from Jameson Land, East Greenland.In Toarcian sediments in Jameson Land, phosphatic concretions at certain horizons contain well preserved Glyphea rosenkrantzi. These crustaceans are confined to the fill of Thalassinoides burrow systems and it is therefore probable that the burrows were constructed by Glyphea. It is possibIe that associated microcoprolites of rod-like shape, without internal canals, may also be ascribed to the Glyphea.A large radiating burrow-system in Jurassic micaceous sandstones of Jameson Land, East Greenland. Large trace fossils consisting of more or less straight burrows radiating from a verticaI shaft are described from Jurassic sandstones of Jameson Land. The mica orientation of the sediment reveals the internal construction of the burrows and aids the interpretation of their mode of formation. The trace fossil has not been previously named and is designated Phoebichnus trochoides ichnogen. et ichnosp. nov.

Middelalderlige stenmortere i Danmark

Middelalderlige stenmortere i Danmark

Deerfield Pilot Test of Recovery by Steam Drive

VALLEROY, V.V., ESSO PRODUCTION RESEARCH CO., HOUSTON, TEX. WILLMAN, B.T., ARABIAN AMERICAN OIL CO., DHAHRAN, SAUDI ARABIA CAMPBELL, J.B., HUMBLE OIL and REFINING CO., OKLAHOMA CITY, OKLA. POWERS, L.W., KINGSVILLE, TEX., MEMBERS AIME Abstract A steam drive of heavy oil was field tested in a shallow, low oil-saturation formation near Deerfield, Mo. The pilot was conducted in the Warner formation, a sandstone containing an 18 degrees API oil having 1,000-cp viscosity at the 60F original reservoir temperature. The formation was at a depth of 160 ft. Steam was injected into nine input wells arranged in an array of inverted five-spot patterns. In the completely confined center pattern, 14 temperature observation wells were installed to obtain thermal data and observe test progress. Late in the test, slugs of ammonia were injected to trace the flow paths of injected fluids. From the test area about 7,000 bbl of oil were produced. Data were obtained on areal and vertical temperature distribution, steam front advance, reservoir fluid movement and terminal saturations. This field test of a steam drivedemonstrated the feasibility of the method,confirmed that the low residual oil saturations observed in the laboratory are obtained in the steam-swept region in the field andprovided recovery and conformance data for one set of field conditions. Introduction The Deerfield steam drive pilot test located in Vernon County, Mo., was conducted in a shallow sandstone containing 1,000-cp oil. The venture was undertaken cooperatively by the research and production departments of Carter Oil Co., which organizations have since been consolidated into Esso Production Research Co. and Humble Oil and Refining Co., respectively. The production department was interested in steam injection at Deerfield because it appeared to be the most promising method of commercially producing this heavy oil deposit. The research department was interested in applying the new recovery method and in evaluating its performance in the field. At the time the test was begun, the initial oil saturation was not well known. Subsequent air coring and early pilot results confirmed that there was too little oil in place for profitable commercial exploitation by steam. Pilot termination at that time, however, would have been premature for evaluating field performance of the process, and the test was continued to obtain additional data on steam injection as a recovery method. DESCRIPTION OF PILOT TEST The test was located about 10 miles north of the town of Deerfield and only a few miles from the Kansas border. The pilot site was selected as typical of the area. The location represented neither the highest nor the lowest oil saturation region in the acreage under lease in 1954. The steam drive was conducted in the Warner sandstone of Lower Pennsylvanian age. At the test site the top of the Warner occurs at about 160 ft subsurface and the formation is a fine- to medium-grained micaceous sandstone that dips gently to the northwest at the rate of 12 to 15 ft/ mile. A cross-section and permeability profile of the test location are shown in Fig. 1. At the pilot location the average total thickness of the Warner formation is about 43 ft, but the effective thickness for steam drive is 26 ft. Two distinct types of hydrocarbon saturation are apparent. The lower portion of the total sand, averaging about 17 ft thick, contains a very heavy asphaltic material that will not flow under the influence of a steam drive. This bottom interval, referred to as a dead oil residue, was not considered as part of the net sand undergoing steam exploitation. The initial formation and fluid properties of the upper 26 ft in the test area are summarized in Table l, and variation of oil viscosity with temperature is shown in Fig. 2. Imbibition tests on preserved core samples taken at the end of the pilot test showed that the Warner sandstone was then neutral or slightly water-wet. Initially, the reservoir may have been strongly water-wet as indicated by low relative permeability to water during both water injection testing and early steam injection. PRIOR HISTORY Initial production tests of wells at the pilot site produced water with only a faint show of oil. No gas was produced except at Well 7-W in the pilot area and at another well about 1/3 mile northeast of the pilot. Prior to the start of the steam drive, a two-well water injection test and a two-well air injection test were conducted. No oil was produced by either. Water was pumped into Well 1-W in the northeast corner of the pilot area with simultaneous production from Well 1 (Fig. 3). The air-injection test was run at input Well 9-W and its offset, Well 2, in the southwest corner. Air and water injectivities were about the same when corrected for viscosity and pressure differences. JPT P. 956ˆ

Geochronology Applied to Exploration Problems: ABSTRACT

The present facilities for isotope age measurements at the Shell Development Company, Exploration and Production Research Division Laboratory, permit measurement by all of the well established age methods--potassium-argon, rubidium-strontium, uranium-lead, and thorium-lead. This gives us the advantage of a wide choice of minerals, and at least among the igneous and metamorphic rocks some age data can usually be obtained by at least one of the methods mentioned. Age measurements are often used to determine the age of igneous rocks encountered in wells. This enables the geologist to judge whether additional sedimentary reservoirs could be expected. In some places the age might suggest that true igneous has been reached and that no further sedimentary section can e reasonably expected. In other places, the presence of igneous sills and dikes, or volcanic layers is suggested, below which additional reservoirs could be expected. Samples of bottom-hole rocks from wells drilled prior to the general use of age determination methods have now been examined with the same objective. In general the results of these measurements on wells in different parts of the United States can be shown to fall in line with the suggested basement periods (G. R. Tilton and S. R. Hart, Science, vol. 140, p. 357, 1963). Frequently age determinations are used to determine time and influence of igneous activities in new exploration areas. In this case surface samples are used. This type of information helps to unravel the structural evolution of an area. This is important background for any study of the hydrocarbon potential of a new exploration province. The use of glauconite for potassium-argon and rubidium-strontium dating of sediments has been common for many years in oil exploration for obvious reasons. The use of the minerals in bentonite to date sediments is the subject of another paper in this symposium (R. E. Folinsbee, H. Baadsgaard, G. L. Cumming, and J. Nascimbene, Radiometric Dating of the Bearpaw Sea). The first dates on both biotite and zircon in bentonites were those measured at the Shell laboratory. Recently we have been measuring the age of detrital minerals in sediments as an aid in determining the source of conglomerates and micaceous sandstones, and this work is continuing. End_of_Article - Last_Page 524------------

Sur les variations d'age et de facies des formations tertiaires sur la bordure meridionale des monts Peloritains (Sicile)

Abstract An Eocene series of calcareous schists and fine grained micaceous sandstones known as the Piedimonte formation in the Zambataro valley of Sicily (Italy) is identical to the Reitano flysch series. A NW-SE trending fault throws the Piedimonte up against the Oligocene to Miocene Peloritani molasse at its southeastern extension. Both formations are unconformably overlain by the Monte Soro flysch. In those areas where the Piedimonte has not been faulted, it is not affected by the Miocene tectonics that deformed the Reitano flysch.

Age relations of the Dunedin volcanic complex and some paleogeographic implications—part I

Abstract Marine inliers at Dowling Bay — Waipuna Bay and Blanket Bay on the northern shores of Otago Harbour are of Waiauan, or at youngest, early Tongaporutuan age. They contain mixed basaltic and trachytic tuffs of the Initial Eruptive Phase at a number of horizons among their upper members, thus fixing the date of initiation of volcanic activity. The beds pass conformably upwards into basaltic tuffs followed by flow-rocks of the First Major Eruptive Phase. The sediments comprise massive and laminated micaceous sandstones, calcareous sandstones and fetid limestones (Dowling Bay Limestone) as well as the interbedded water-lain tuffs. All these, up to the top of the highest sandy layer at Waipuna Bay, are grouped as the Waipuna Bay Formation. They are derived mostly from the Otago schists, but contain minor microcline of granitic or high-grade metamorphic parentage. Outward dips of the sediments and overlying volcanics are ascribed to doming by magmatic intrusions.

Pennsylvanian Rocks of Eastern Interior Basin

Pennsylvanian rocks of the Eastern Interior basin underlie about 53,000 square miles in Illinois, Indiana, and western Kentucky, with small outliers in Missouri and Iowa, attaining maximum thickness of about 2,500 feet in southeastern Illinois. At the beginning of the Pennsylvanian there was a regional southwest slope furrowed by numerous subparallel valleys as deep as 200 feet. An eastward slope prevailed along the western border of the basin with smaller valleys. Subjacent strata range in age from the Middle Ordovician St. Peter sandstone to the Upper Mississippian Kinkaid limestone. Because of topographic unevenness and early Pennsylvanian tectonism, the early Pennsylvanian Caseyville and Tradewater units vary from zero to 1,200 feet. Movements along the LaSalle anticl ne and Duquoin monocline are reflected in an isopach map of this interval. In later Pennsylvanian Carbondale and McLeansboro time the intervals increase regularly toward the southeast, showing that the present southeast border of the basin is due to post-Pennsylvanian deformation. Structural relief on the No. 2 coal ranges from +700 to -913 feet. Similar systems of nomenclature are used in Illinois and Kentucky but different names are employed in Indiana. The significant features of 46 key beds are described. Clastic ratios average about 8 parts clastic to 1 non-clastic. Sand-shale ratios are extremely variable due to lenticular sandstones at more than 20 positions. Many sandstones occupy channels excavated into underlying strata; others seem to be off-shore barrier beach deposits. There are marine limestones at about 25 different positions, generally thickening toward the western border of the basin, but each has its individual pattern of distribution. Lower Pennsylvanian sandstones are highly quartzose and derived from older sediments; later sandstones are micaceous and feldspathic with much interstitial clay, evidently a first-cycle deposit from a metamorphic terrane. Coals are generally banded, and range in rank from high-volatile to medium-volatile bituminous. Refractory underclays ar found in the Lower Pennsylvanian in northern Illinois and in the area near St. Louis, Missouri. Cyclic sedimentation is very well displayed with at least 25 alternations of coal, marine limestone, shale, sandstone, and underclay. Early Pennsylvanian sediments came from the east and northeast but the source of the later micaceous sandstones is still uncertain. Most marine invasions came from the west, north of the Ozark uplift, but some in the early Pennsylvanian probably entered the basin from the east and south. The basin has produced about 5 billion tons of coal and 325 million barrels of Pennsylvanian oil. Other industries based on Pennsylvanian materials are refractories, common brick and tile, road metal, agricultural limestone, portland cement, rock asphalt, glass sand, foundry sand, and whetstone.

A PETROGRAPHICAL STUDY OF MEDIAEVAL HONES FROM YORKSHIRE

Summary Honestones from York and certain other early mediaeval sites prove on petrographical examination to include the following rook types: quartz-mica granulite, quartz-muscovite-chlorite-schist, metamorphosed siltstone, silty sandstone, chloritic siltstone, mudstone, phyllite, micaceous sandstone and siltstone, glauconitic sandstone. The metamorphic granulites and related rocks are similar to the schist hones of Mr. G. C. Dunning. The possibility of a source in Aberdeenshire is suggested, perhaps indicating an ancient trade route with the north. Typical phyllites and siltstones from the Lower Palaeozoic rocks of NW. England and the Southern Uplands were probably obtained from the local glacial drift. The sandstones include some Yorkshire Millstone Grit types, while the glauconitic sandstone is undoubtedly from the Greensand of SE. England. It is noted that all the honestones consist of rocks made up of small angular quartz grains set in a softer matrix.

Stratigraphy of Southeastern Turkey

In the stratigraphy of southeastern Turkey the Paleozoic is represented by more than 2,000 meters of Cambro-Ordovician composed largely of micaceous sandstones, some siliceous limestones and pyroclastics in the region of Telbesmi, west of Mardin, and by limestones and marly limestones of Permo-Carboniferous age in the eastern part of the area. The basal quartzitic part of the latter contains forms suggesting Upper Devonian age. The Permian underlies the Triassic without an unconformity. The Mesozoic section, which is principally calcareous, maintains that facies to the middle of the Cretaceous. The Upper Cretaceous is composed principally of argillaceous shales which continue into the Paleocene. The lower part of the Eocene is arenaceous, but the Lutetian is an extensivel developed thick limestone. The upper part of this limestone is chalky and soft. This latter part is considered upper Eocene and may extend even higher. The Miocene is represented by siliceous and gypsiferous limestones and shales. The very extensive development of the Pliocene in the continental facies suggests similarity to the Bakhtiari series of Iraq.

Permian Redbeds of Kansas

The Permian redbeds of Kansas are re-studied in detail with reference to Cragin's type sections and original classification, to which correlations have been made for more than 40 years, this paper enlarging on an unpublished paper, Lower Red-Beds of abstracted in the Bulletin of the American Association of Petroleum Geologists, Vol. 21, No. 12 (December, 1937), pp. 1557-58. The Cimarron series includes all of the Permian redbeds overlying the salt-bearing and gypsum-bearing gray of the Wellington formation. From the base upward, the names and thicknesses of the subdivisions are given. The two lowermost units, the Estheria-bearing Ninnescah shale, 425 feet thick, and the Stone Corral dolomite-anhydrite, 0-6 feet thick (although much thicker in subsurface), have been excluded from Cragin's the latter being here restricted to two higher members: the Chikaskia 145 feet thick, and the Kingman 80 feet thick. The basal part of the Ninnescah becomes the Garber sandstone in Oklahoma, while its upper part plus the Chikaskia are the equivalent of the type of Oklahoma. The Kingman sandstone has been mis-correlated often with the Oklahoma Duncan, a much higher formation. Cragin's Plain measures, 275 feet thick and in few places well exposed, has been mis-called Hennessey in Oklahoma where exposed beneath typical Duncan sandstone. The Cedar Hills 180 feet thick, is correlated with the true Duncan of Oklahoma, while the selenite-veined Flower-pot shales, 190 feet thick, have been called Chickasha in Oklahoma. The name Nippewalla is suggested for the group of formations lying between the Stone Corral and Blaine evaporites. Cragin's Cave Creek is identical with the Blaine formation of Oklahoma, is 84 feet thick, and is divided upward into four beds of gypsum: Medicine Lodge; Nescatunga, a bed in Cragin's clay; Shimer (Lovedale of Noel Evans); and Haskew. Where these gypsums are well developed, only 15 feet of Cragin's Dog Creek separate them from the Whitehorse sandstone. At Dog Creek, the type locality, however, with the three upper beds absent because of solution, the separating clays to the base of the Jenkins have been included in the 53 feet of Dog Creek shales, the highest unit of Cragin's Salt Fork division of the Cimarron series. From the base upward, the Kiger division begins with the Whitehorse a formation 265 feet thick, the name replacing Cragin's Red Bluff (pre-occupied and dropped). It falls into four natural subdivisions or members: Marlow 110 End_Page 1751------------------------------ feet thick; Relay Creek dolomites with their included veined sandy shales, 22 feet thick; an even-bedded 100 feet thick; and a red shale member, 38 feet thick, with local thin dolomites at middle and base, the last two being equivalent to the Rush Springs-Cloud Chief of Oklahoma, although Cloud Chief gypsums are not recognized in Kansas. No channel-sands of the type Verden or type Whitehorse facies of the Marlow have been noted in Kansas, although calcareous, cross-bedded sandstones are found associated with the Relay Creek dolomites. Capping the Whitehorse commonly in a bold scarp, is the Creek of Cragin, a single bed of dense, in many places cherty, dolomite 2 feet thick. This bed in turn is overlain by gray and red (Hackberry shales of Cragin, name pre-occupied, dropped) and Big Basin sandstone, totalling 65 feet, previously combined under the latter name, which are probably correlative with the lower beds of the Quartermaster formation (restricted) of Oklahoma, these beds terminating the Kansas redbed exposures, with the possible exception of a small exposure in Morton County, not studied by the writer, which is mapped as Triassic by the Kansas State Geological Survey. Possible horizons of unconformity have been studied critically, the evidence indicating nothing greater than local disconformity, the more pronounced stratigraphic abnormalities ordinarily due to removal of soluble beds by ground waters, resulting in slumpage and collapse-brecciation of the overburden, a condition to be expected of beds in contact with the major dolomite-anhydrite formations, which are the Stone Corral, the Blaine-Dog Creek, and the Day Creek. The excellence of these evaporite formations as key horizons in redbed stratigraphy is emphasized in contrast to the variable lithology of the intervening red siltstones and their included lenses of rounded, frosted, orange-polished or micaceous sandstones, on which scant dependence can be placed, as shown on subsurface cross se tions. A cross section depicts a progressive wedging-out of the various members of the Wellington and Harper formations westward against the Sierra Grande arch of eastern Colorado, where beds of approximate Salt Plain age rest on beds near the top of the Pennsylvanian (Wabaunsee) as accepted by the Kansas Geological Survey, the one real unconformity of regional significance discovered.

Megalithic Monuments of South Wales

THE latest addition to the Megalithic Survey of England and Wales (“Map of South Wales showing the Distribution of Long Barrows and Megaliths”. Compiled by F. W. Grimes. Southampton: Ordnance Survey. Pp. 56 and Map: Scale 4 miles to 1 inch. 5s., 6s. 6d. and 6s. 6d. net) incorporates the results of a survey of the area covered by Sheet 7 of the Quarter-inch Ordnance Map. It is now possible for the first time, as the Director-General points out in an introductory note, to assess the distribution of the megalithic monuments of an area which has been recognized as an important centre of the culture. This region, predominantly upland, and, therefore, differing essentially from others already covered by the series, falls into two parts, a narrow coastal plain of undulating country, seldom more than 400 ft. above sea-level, in which the monuments are mainly found, and an upland, which attains its greatest heights in Brecknock Beacons, and of which a large part is above the 1,000 ft. contour line. Mr. Grimes discusses a number of questions arising out of the distribution of the monuments, not the least interesting being those relating to his omissions, a matter with which he proposes to deal at greater length elsewhere. He also raises a question of wide general interest in connexion with Stonehenge. One of the most noteworthy contributions to British archaeology of the post-War years was the conclusion, at which the late Mr. H. H. Thomas of the Geological Survey arrived in 1923, that the blue stones of the inner circle at Stonehenge were igneous rock derived from the Presely Mountains and the altar stone micaceous sandstone of either the Cosheston Beds around the estuary of Milford Haven, or the Senni Beds of Carmarthen and Brecknock; but up to the present no satisfactory hypothesis as to the method of transport and route has been offered. Mr. Grimes discusses the question, in the light of his survey and gives his reasons for suggesting a route by both land and water in which transport from the Presely Mountains to the sea was effected by one of three possible ancient roads which he shows.

A New Plant ( Thallomia ) showing Structure, from the Downtonian Rocks of Llandovery, Carmarthenshire

The curious fossil which is here described and figured was discovered in a quarry about 50 yards north-west of Capel Horeb on the main road between Llandovery and Brecon (fig. 1). Most of the rocks of the quarry consist of thickly bedded, bluish-grey, highly micaceous sandstones (Tilestones) of Lower Downtonian age, which locally approach quartzites in composition. Many calcareous bands of fossils are intercalated with these Tilestones. The fossil fauna of this quarry and of others in the immediate neighbourhood has been noted and recorded by several workers, including Dr. L. D. Stamp and, more recently, Mr. S. H. Straw, who records the following fauna from this horizon:— Cornulites serpularius Sclotheim. Small Rhynchonellid. Cucullella antiqua (J. de C. Sowerby). Grammysia extrasulcata Salter. Modiohpsis complanata (J. de C. Sowerby). Bellerophon trilobatus (J. de C. Sowerby). Holopella obsolete (J. de C. Sowerby). Platyschisma helicites (J. de C. Sowerby). Orthoceras sp. Kloedenia (Beyrichia) wilckensiana (Jones). Fragment of a fish spine. The plant recorded in this communication has been obtained, not from the sandstones which occupy the major part of the quarry, but from a lenticular patch of gritty micaceous shales which is interbedded with them (PL XLIII, fig. 1). The lenticle is bounded by a lighter-coloured zone, 4 inches wide, of fine-grained

THE LOWER PERMIAN AT ASHFIELD BRICK AND TILE WORKS, CONISBOROUGH

(Read November 25th, 1915.) This section has long been under observation by Yorkshire geologists, but no detailed record has hitherto been given of the Lower Permian beds as exposed here within the last few years. The chief interest has been centred upon the Upper Coal Measures upon which the Permian rests, beds which have yielded a rich harvest of fossil-plants. The top-most bed of the Coal Measures is a fine-grained micaceous sandstone deeply stained with hematite. The surface of this sandstone is undulating, and in the hollows are found deposits of Permian age, consisting of conglomeratic material. The largest pebbles in this conglomerate are in general not more than an. inch in diameter, but during a visit to the section in September, 1915, some large boulders up to eighteen inches in diameter, were found, which had been taken out of the conglomerate by the workmen. These boulders consisted of sandstone, identical with the underlying Coal Measure sandstone, and a dense siliceous sandstone also possibly a Coal Measure type. Intercalated with this conglomerate are beds of fine sand, which sand is in all respects, except colour, like the sand which occurs in similar stratigraphical positions along the edge of the Permian escarpment from North-east Durham to Yorkshire. As the section shows, this lowest bed is in its thickest part about 5 ft. 6 ins., but in a distance of 15 ft., it has thinned away to 15 ins. of fine sand with very few pebbles. Resting upon this bed and traceable ...