Stratigraphic Conditions Research Articles

Subsurface Study of Morrow and Atoka Series in Part of Arkansas Valley of Western Arkansas

The Morrow series of the Arkansas Valley is primarily a sand and shale section in the southern and southeastern parts of the area, changing to a limestone and shale section on the foreland at the northwest. Wells drilled in the area have penetrated thicknesses of Morrow ranging from 250 feet to more than 1,200 feet. The sandstones of the Hale formation produce gas in several fields and have considerable promise for future production. These beds are also possible oil reservoirs. The Atoka series consists of alternating beds of sandstone, shale, and siltstone. Regional bed-for-bed correlation of the various units is impossible at this time, due to lack of closely spaced wells. Sand zones in the Atoka are the major gas-producers in the area and have many possibilities for future production. The Cecil field study illustrates a possible regional exploratory approach, if correlation problems are ever solved. Many of the structures in the Arkansas Valley are untested. The anticlines in the central and northern parts of the area are more favorable for oil and gas production, as they are less tightly folded than those of the southern part. The Cecil anticline is a complexly faulted structure with faulting and sedimentation apparently occurring concurrently. Structural and stratigraphic conditions for the occurrence of radioactive minerals are favorable. However, none has been reported although there has been limited prospecting activity near the area.

Information vs. Cost in Exploratory Drilling: ABSTRACT

This is a two-part paper consisting of an analysis by an engineer of the costs of obtaining information in exploratory drilling, and a statement by a geologist of the basic information desired. End_Page 433------------------------------ The cost of exploratory drilling is usually higher than development drilling because of more unknown factors, such as depth of objectives and incomplete knowledge of structural and stratigraphic conditions. Services are often requested by the geologist that may not evaluate potentially productive zones but aid in the geological interpretation. The cost is charged to the well, nevertheless. In order to drill exploratory holes in the most economical manner the fullest use must be made of those information gathering techniques which obtain information as the drilling progresses, that cause neither slowdown nor shutdown of drilling operations. This information must be closely watched and diligently recorded by the geologist in order to minimize the use of more expensive and more time-cons ming information tools. The practice of exploring in long rat-hole intervals, in particular, appears in analysis to be extremely costly and time-consuming, and recent improvements in formation-testing equipment render it impractical. All operations which increase drilling time and the number of round trips increase drilling hazards as well as direct costs. End_of_Article - Last_Page 434------------

Geology of Keyes Field, Cimarron County, Oklahoma: ABSTRACT

The development of the Keyes field as a major gas reservoir in the lower Morrow sand has done much toward instigating the current wildcat play throughout the Hugoton Embayment, and Dalhart and Anadarko basins. This field, although discovered in 1943 by the Pure Oil Company, produced gas with a low 825 BTU, and development stagnated until a subsequent Coltexo discovery of high BTU gas in the upper Morrow (Purdy sand) incited major companies to exploit their leases. The exploitation of the Purdy sand for high BTU gas failed to develop substantial reserves; however, it did succeed in delineating the Keyes sand, although low BTU gas, as a major gas field. The Keyes is considered to be a blanket clastic sand of Lower Pennsylvanian age, deposited on an erosional surface of late Mississippian time. Pre-Pennsylvanian structure and some later rejuvenation apparently are responsible for the accumulation, with porosity and permeability controlling local production. Stratigraphic conditions vary markedly throughout the columnar section, indicating numerous alternating shallow marine and continental environments of sedimentation. These abrupt facies changes may offer additional zones of production. Though the Keyes sand is the major producer in the field, the Purdy (upper Morrow) and the Cherokee (lower Des Moines) have been proved for production in parts of the field. To date, 107 wells have been completed in the Keyes sand, having a calculated reserve of 514,120,000,000 cubic feet of gas. End_of_Article - Last_Page 428------------

Prejudice, Progress, and Promise in Rocky Mountain Oil Exploration: ABSTRACT

The evolution of an exploration philosophy in the Rocky Mountain area can be reviewed in terms of the new areas involved in each successive wave of exploratory vigor. Such an analysis indicates an exploration history which comprises five episodes, each dominated by a set of guiding principles, controlled by the available data and tolls, and governed by the economics of the times: (1) discoveries related to seeps and other near-surface indications; (2) the location of major surface structures and the establishment of production in the majority of Rocky Mountain provinces; (3) detailed surface mapping, leading to the discovery of further anticlinal accumulations; (4) widespread application of geophysical tools, coupled with deeper drilling on known features; (5) geophysical and subsurface geology applied to the refinement of deeply buried structures and structural-stratigraphic traps. Signs of the emergence of a new era can be seen. During each of these episodes certain areas and certain parts of the stratigraphic section were condemned without trial; some for economic reasons which no longer pertain, others on the basis of a variety of geologic concepts developed to satisfy a local situation and then applied broadly as sweeping generalizations. Examination of the complex tectonic and depositional history of the Rocky Mountain area suggests that at least six successive and different patterns have been impressed upon the structural and stratigraphic record. In terms of oil accumulation each pattern may be shown to have its own internal constitution, governed by tectonics, environment, and sediment-source, and an independent set of potential truncation and permeability traps related to post-depositional events. No ondemning generalization arrived at through experience with one of these varying patterns may safely be applied to the others and no area may be considered non-productive until the inherent possibilities of each pattern represented are tested. End_Page 529------------------------------ It may be shown that every major oil accumulation in the area is related to a combination of structural and stratigraphic conditions with increasing evidence to indicate that stratigraphic controls are dominant. Many of the stratigraphic factors can be analyzed through study of the rocks themselves and by interpretation of their geophysical responses. With the abundant outcrops of the Rocky Mountain area, the increasing availability of subsurface data, and the developing know-how whereby these data may be related to oil occurrence, there remains a broad and encouraging field for an expanding exploration program. End_of_Article - Last_Page 530------------

Geology and Oil and Gas Possibilities of Western Washington.: ABSTRACT

The state of Washington is one of the few potential oil and gas provinces in the United States in which no commercial production has been developed. Market demand for oil and gas in the Northwest would make any discovery very attractive economically. This paper deals with that portion of Washington situated west of the Cascade Mountains, approximately the western one-fourth of the state. An aggregate of over 50,000 feet of marine. Tertiary sediments of Pliocene, Miocene, Oligocene, and Eocene age are present. The stratigraphy varies greatly from one sedimentary basin to another, and up to 20,000 feet of sediments have been found in some of the basins. Volcanics varying greatly in thickness, according to their distance from their source vents, are common in the middle and lower Eocene. A few hundred feet of Miocene lavas extend part way across southwestern Washington. Structural conditions of the area are typical of coast-range structure, except for the Olympic Peninsula area. The sediments of the western Olympic Peninsula have been folded, faulted, and crushed into one of the most complex structural conditions found anywhere in the world. Most geologists who have worked in the area believe that commercial oil and gas discoveries will be made. Oil and gas seeps are present and in several areas sub-commercial production has been found. Source beds are abundant and permeable sands are present in all formations. Contrary to popular opinion, the lack of successful discoveries to date can be attributed more to poor structural locations of the wells drilled, rather than to lack of reservoir rocks. Exploration is difficult, not only because of the complex structural and stratigraphic conditions, but surface exposures are limited by extensive glacial deposits and thick growth of forests and underbrush. Subsurface data are needed for intelligent exploration. End_of_Article - Last_Page 2775------------

Developments in Wyoming and Idaho in 1951

Exploratory drilling set new records in Wyoming during 1951. The 200 wells drilled with a total footage of 1,038,762 feet represented an increase of 14 per cent in wells drilled and 22 per cent in footage drilled over the previous record exploratory year, 1950. In 1951, 42 successful exploratory wells were completed, the discovery rate being 21 per cent as compared with 23 per cent in 1950. In the new-field wildcat category, 11 of the 110 tests (10 per cent) were successful. Seismic exploration was employed in 10 of the new-field discoveries. The majority of the 42 discoveries in 1951 involved stratigraphic trap or fault trap conditions controlling the accumulations. Faulting is considered an important accumulation factor in 7 of the 11 new fields discovered in 1951. Sign ficant discoveries included Whistle Creek, West Sussex, North Fork, and East Salt Creek as new fields, and new pools at South Cole Creek, Sussex, Beaver Creek, and South Elk Basin. The Slick Creek field was considerably enlarged. Geophysical activity in Wyoming was moderately greater in 1951 than in 1950, with 1,295 crew-weeks of seismic and 243 crew-weeks of gravity effort. Of the total seismic effort 65 per cent was concentrated in the Powder River and Big Horn basins. Wyoming oil production in 1951 set a new record of about 69 million barrels, 14 per cent above the 1950 production. Gas production totalled 83 million MCF, 5 per cent above the 1950 production. Sulphur production from the processing of natural gas totalled about 111,900 long tons in 1951. Idaho continued as a state having no oil production. Developments during 1951 were restricted to southeastern Idaho where a deep Mississippian test was drilled on Juniper anticline and where blocks of leases were taken on other surface structures.

Preliminary Report on Whitemud Oil Field, Alberta, Canada

The Whitemud oil field of the Edmonton district is described as known to date. It produces Leduc-type high-gravity oil from the Quartz Sand series of the Lower Cretaceous. Structure is believed to be anticlinal with stratigraphic conditions closely controlling the position on structure of producible oil accumulations. Dips are extremely gentle and are thought to have originated from differential compaction of the Cretaceous rocks over irregularities on the eroded Devonian surface as well as differential uplift in post-depositional time. Possible ages and origins of the oil are discussed. The name, Ellerslie member of the Blairmore formation, is proposed to designate the sediments currently known as the Lower Cretaceous Quartz Sand series in the Edmonton-Leduc district. The Imperial's Whitemud well No. 3 is proposed as the type well-log, since no outcrops are definitely recognized as equivalents of this sand, due primarily to its lenticular nature.

Mammutfynden från Ramsele och Sollefteå

Abstract Two new finds of fossil mammoth molar-teeth from Ramsele and Solleftea in the province of Angermanland are described. A survey of the Swedish finds hitherto of mammoth remains in twelve localities is given. Stratigraphical conditions prove that the mammoth lived during the last Interglacial period.

LaGrange Oil Field, Adams County, Mississippi: ABSTRACT

The LaGrange field, Adams County, Mississippi, is the largest field producing from the Wilcox in Mississippi. Originally a Tuscaloosa field opener in February, 1946, the discovery well was plugged back and recompleted as a Wilcox producer in August of the same year. Production is being recovered from several sands of the middle Wilcox at a depth of approximately 6,200 feet. In its short life, the field has been extended to encompass 3,000 acres. As of January 1, 1949, it had 99 producing wells (including 19 twins) and had a cumulative production of more than 3 million barrels. Daily runs are in excess of 11,000 barrels. With the field still not completely defined, eventual production is estimated in excess of 15 million barrels. The field is located on the flank of the Mississippi basin. The local structure is an elongate west of south-trending anticlinal nose. Although closure is developed on a series of nodes along the axis of the fold, reservoir traps are, in good part, controlled by stratigraphic conditions. Discovery of the field resulted from combination of geophysical and subsurface information. End_of_Article - Last_Page 2070------------

Sampling and Examination of Well Cuttings

Samples of well cuttings are one of the chief sources of information concerning the formations of the subsurface in the Mid-Continent and Permian basin areas of the United States. By careful use in applying the methods of collecting and preparing these samples as described in this paper, it is possible to obtain cuttings samples which are truly representative of the formations penetrated. By microscopic examination of these samples, it is possible to prepare descriptions and plotted logs which give an accurate picture of the rocks penetrated. These logs can be correlated so as to reveal the stratigraphic conditions in the subsurface and trace time horizons through various facies variations of the subsurface formations. These time horizons can be used in the structural int rpretation of the region. Detailed descriptions of cuttings samples from pay sections can be used, by methods outlined in this paper, in making estimates of oil and gas recovery from a field, in reservoir studies, and in guiding well remedial work.

EARLY MAN IN AMERICA INDEX TO LOCALITIES AND SELECTED BIBLIOGRAPHY, 1940–1945

Research Article| October 01, 1947 EARLY MAN IN AMERICA INDEX TO LOCALITIES AND SELECTED BIBLIOGRAPHY, 1940–1945 E. H SELLARDS E. H SELLARDS TEXAS MEMORIAL MUSEUM, AUSTIN 22, TEXAS Search for other works by this author on: GSW Google Scholar GSA Bulletin (1947) 58 (10): 955–978. https://doi.org/10.1130/0016-7606(1947)58[955:EMIAIT]2.0.CO;2 Article history received: 06 Dec 1946 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation E. H SELLARDS; EARLY MAN IN AMERICA INDEX TO LOCALITIES AND SELECTED BIBLIOGRAPHY, 1940–1945. GSA Bulletin 1947;; 58 (10): 955–978. doi: https://doi.org/10.1130/0016-7606(1947)58[955:EMIAIT]2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract This paper, containing notice of the principal investigations of early man in America for the years 1940 to 1945 inclusive, is a continuation of a similar compilation for the years 1839 to 1939, published in 1940. Special attention is directed to the conditions of occurrence and to the associated fossils. The term early man is used to apply to human materials that, from the stratigraphic conditions, associated fossils and artifacts, or for other reasons, are believed to be of some appreciable antiquity in a geologic sense. Contributions of recent years include a considerable number of papers relating to the time interval between the disappearance or reduction of the great mammalian fauna of the Pleistocene and pottery-bearing horizons. The climatic fluctuations within this time interval have likewise received attention. The stratigraphic units of the early Recent are being differentiated and named and the contained human materials studied. Through the years some progress has been made in determining the implements used by early man in hunting for and processing particular animals; those used in hunting the bison and elephant are among the best known. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Gelogical Occurence of Oil in United Kingdom with Reference to Present Exploratory Operations

The United Kingdom has been actively prospected for oil since 1936 by several major companies, but during the war no details have been released although oil has been commercially produced during this period. The question of oil occurrence in the United Kingdom is discussed in detail on the basis of fundamental geology, and it is shown from geological history that since Devonian time this country has lain far outside the zones of geosynclinal sedimentation and instead has formed part of the eastern edge of the postulated Atlantean Continent, whereby it has either been a land area for much of succeeding geological time or else has been covered by shallow shelfseas with relatively thin sedimentation. Locally, suitable environments for oil generation may have occurred in the arboniferous and Jurassic. The United Kingdom has been the meeting place of three major orogenic movements in which violent folding has taken place followed by lengthy erosion periods. The geological pattern of the United Kingdom is characterized by a number of rigid Lower Paleozoic massifs, either exposed or only shallowly buried, with intervening downwarps containing locally thick Upper Paleozoic and Mesozoic sediments. Oil indications occur over much of the stratigraphical column, particularly in Carboniferous and Jurassic rocks, and are commonly found in close and apparently genetic association with non-marine sediments. Suitable stratigraphical and structural conditions for oil pooling occur in southern England and east-central England but widespread testing has proved commercial pr duction only from the English equivalent of the lower Pottsville, Pennsylvanian system, in the latter region. It is concluded that the oil prospects of the United Kingdom are definitely restricted both stratigraphically and areally by reason of the geological factors which have together contributed to its development. More pools may be found but nothing of large dimensions is expected.

Developments in Louisiana Gulf Coast in 1944

In 1944, 492 wells were drilled in Louisiana Gulf Coast, an increase of 144, or 41 per cent, over 1943. Of the total, 57 wells, or 11.6 per cent were wildcats, 13 of which, or 22.8 per cent, discovered new fields. Four hundred thirty-five wells were drilled in 103 of the district's 153 fields producing prior to 1944, and development wells had been drilled in seven of the 13 new fields by the close of the year. Eight fields formerly classified as gas or distillate fields became oil fields in 1944; 15 of the old fields were given major extensions; and important new sand discoveries were made in 24 additional fields. Three hundred thirty development wells were completed as producers and 105, or 24 per cent of the total, were abandoned. Reflection-seismograph, subsurface geology, and gravity-meter work were the chief methods by which new fields, extensions, and new sands were found. Geophysical activity increased for South Louisiana during the year from an average of 33.5 crews working throughout 1943 to 38.67 in 1944. Reflection-seismograph crews increased from an average of 27 in 1943 to 32.78 in 1944 and only a total of 7 crew-weeks of torsion-balance work and 22 crew-weeks of refraction-seismograph work was done this year. Gravity crew-weeks decreased from an average of 6.5 for 1943 to 5.33 for 1944 and no appreciable exploration was carried out by core drilling, surface geology, or magnetometer. More acreage was taken under lease than in the preceding year with a slight increase in the average prices paid. Development by the close of the year indicates that of the 13 newly discovered fields 6 may be expected to have reserves exceeding 10 million barrels, 3 may exceed 5 million, and the remaining 4 are inadequately developed to give an estimate of their size. While new fields have increased the reserves for South Louisiana, there has been a much greater increase from extensions, new sands, and new structural reservoirs in old producing fields. The age of the discovery sands are given in this paper according to the usage of the operators in each field. The high proportion of field dry holes largely results from the very complicated nature of many of the structures in South Louisiana. Intricate faulting, extremely steep dips, or abrupt changes in stratigraphic conditions are common to most of the structures of this area. In addition, drilling hazards characteristic of South Louisiana are responsible for many dry holes. Among these are heaving shale, salt water flows, and great depths to which wells must be drilled. Forty-eight per cent of all the wells drilled were below 10,000 feet and 98 wells were drilled below 11,000 feet. Only a third of all the wells drilled were less than 9,000 feet deep and only 17 wells were drilled to depths less than 5,000 feet. The geological significance of important wells in the area is discussed and the basis on which the discovery wells were drilled in 1944 is given where possible.

Kettleman Hills North Dome: ABSTRACT

Kettleman Hills North Dome oil field, discovered in 1928, occupies a long narrow anticline on the west side of the San Joaquin Valley, California. The oil field is about 15 miles long and 2 miles wide. The crest of the anticline has been eroded, leaving exposures of the underlying formations so obvious that the structure was recognized many years ago. However, inferences about the extent and position of the oil accumulation, prior to the development of the field, were wrong. The history of this field provides an excellent illustration of the growth of geologic knowledge, and is discussed at some length. Effective January 31, 1931, a unit plan of operation was adopted by the various lessees of Government land in the field. In November, 1932, a map was drawn in an attempt to establish the position of the 7,000-foot subsea structural contour. The position of this contour was agreed on by the member companies and was accepted as defining the probable productive area. Subsequent events have only slightly modified the general opinion about position of the 7,000-foot contour, but the productive area has proved to be substantially different than was originally believed. Development of the field, including the drilling of unproductive outpost wells, has demonstrated that production extends below the 7,100-foot subsea contour on both the northwest plunge and the northeast flank, while on the o posite plunge and flank, it reaches only about the 6,500-foot subsea contour. The latter flank is much the steeper. What has caused this inclination? Various reasons are suggested, some of which are not original with the author. 1. Remnants of a dissected peneplain suggest a slight warping of the structure after accumulation had occurred following the main folding in middle Pleistocene time. An inference is drawn that cementation of the sands at the oil-water interface had prevented fluid readjustment. 2. Since the southwest flank is steeper than the northeast, the strata on that flank could have been subjected to more compression and End_Page 1777------------------------------ alteration, and have caused the permeability here to be reduced as compared with the opposite flank. 3. The presence of a much higher hydrostatic head on the mountainward or southwest flank as compared with its valleyward counterpart has also been offered as an explanation. In this connection, it has been argued that the difference in specific gravity of the oil and water is not sufficient, with a 600-foot hydrostatic head, to overcome the obstacles of surface tension, friction, and cementation on the high side of the water table. 4. Capillary-gravity action has also been considered a factor. 5. Finally, it has been suggested that the northeast flank had a much greater drainage area from which to draw its oil supply than did the southwest flank. The fact that the anticline is en echelon with the adjoining structures at both ends, suggests that the forces causing this condition may have had a longitudinal component that could have tilted the north dome structure northward. Other structural and stratigraphic conditions in the field which might bear on the problem of an inclined water table are discussed; and questions are raised as to how much the genesis and migration of petroleum might be involved in a possible solution of the problem. End_of_Article - Last_Page 1778------------

A Silurian Graptolite Zone in Crane County, Texas: ABSTRACT

In June, 1941, William Hilseweck of the Gulf Oil Corporation of Fort Worth, Texas, sent the writer a piece of core from a well taken at a depth of 9,340 feet in Crane County, Texas. While he did not determine the species, he correctly concluded that the graptolites on the core proved the presence of a Silurian zone for one which had commonly been called Devonian. A few fragments of graptolites occur on the surface of the core, but they have sufficiently diagnostic characteristics to identify the species. The stratigraphic conditions are noted, and the species is illustrated and described. Also, it is compared with specimens of the same species which were sent to the writer from the Chicago region by Alfred and Helen Loeblich. End_of_Article - Last_Page 905------------

Marine Sedimentation and Oil Accumulation on Gulf Coast: ABSTRACT

The sands of the Gulf Coast are prolific petroleum reservoirs. Deposition of these sands has taken place during a series of advances and retreats of the sea. A resume of the sedimentation and depositional conditions occurring in a advance, or transgression, and in a retreat, or regression, is presented. The resulting stratigraphic sequences, the marine overlap and marine offlap are discussed under ideal conditions, and illustrated by electrical log profiles. Particular reference is made to possibilities for petroleum accumulation as influenced by stratigraphic conditions. Sands deposited in a transgressive sea, such as the Cockfield, upper Wilcox (Sabinetown), Marginulina-upper Frio, and lower Miocene sands, are believed to present conditions favorable for the migration, accumulation, and recovery of oil. Although sands deposited in a regressive sea, such as parts of the Rockdale (Wilcox), lower Yegua, Vicksburg-lower Frio, and Catahoula, are not considered theoretically as favorable, local structural or environmental conditions may effect excellent reservoirs. The compound features representing a invasion followed by a retreat, or the reverse, are also considered and electrical log profiles presented. The economic significance in petroleum geology of the resultant sand wedges and shale wedges is discussed. End_Page 930------------------------------ It is suggested that both local and regional studies of producing horizons be made in the light of the theory of the marine overlap. End_of_Article - Last_Page 931------------

Forests of the Yarmouth and Sangamon Interglacial Periods in Illinois

The Pleistocene or glacial period, which lasted approximately one million years, brought about many changes in the stratigraphical, topographical and biotic conditions in the northern half of North America. During a portion of that period at least 4,000,000 square miles of land were covered with ice of enormous thickness. The Pleistocene may be divided into the following glacial and interglacial stages:

Lower Cambrian Olenellus zone of the Appalachians

Research Article| February 01, 1938 Lower Cambrian Olenellus zone of the Appalachians CHARLES ELMER RESSER; CHARLES ELMER RESSER Search for other works by this author on: GSW Google Scholar BENJAMIN FRANKLIN HOWELL BENJAMIN FRANKLIN HOWELL Search for other works by this author on: GSW Google Scholar GSA Bulletin (1938) 49 (2): 195–248. https://doi.org/10.1130/GSAB-49-195 Article history received: 04 Jun 1936 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation CHARLES ELMER RESSER, BENJAMIN FRANKLIN HOWELL; Lower Cambrian Olenellus zone of the Appalachians. GSA Bulletin 1938;; 49 (2): 195–248. doi: https://doi.org/10.1130/GSAB-49-195 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract INTRODUCTIONLower Cambrian fossils were first discovered by Emmons in eastern New York almost a century ago. Since then, many specimens have been obtained from the Appalachian region, but the stratigraphy received little attention. Recently, interest in the study of the early Paleozoic rocks of the Appalachians has revived.A. F. Foerste described the cystids. Consequently, the new genus Lepidocystis and the species L. wanneri are to be attributed to him.THE APPALACHIANSIn this paper the name Appalachians applies to a region characterized by a particular stratigraphic history and geologic structure and, therefore, is not used in a physiographic sense. The region embraces the Appalachian Mountains from Alabama to eastern Pennsylvania, or the area to which the physiographic term usually applies. Inasmuch as similar stratigraphic conditions and geologic structure continue beyond Pennsylvania, the term Appalachians must also embrace the Hudson and Champlain valleys, and the St. Lawrence Valley to . . . This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Developments in North-Central Texas and the Panhandle, 1936-1937

Production in north and west-central Texas is principally from beds of Pennsylvanian age and is controlled both by structural and stratigraphic conditions. The largest single unit of new production discovered and developed in north-central Texas during 1936 is from lenticular Strawn sands at a depth of about 2,000 feet in the Anderson and Kerr field located southeast of the town of Gainesville, Cooke County. The field is located on an eastward plunging structural nose situated on the northeastern flank of the Muenster arch, is defined by 104 oil wells and 16 dry holes, and covers about 550 acres. With a 40-barrel per well allowable, the daily production is about 4,000 barrels of 40° gravity oil. The greatest unit of drilling activity in the district today is north and east of the town of Bryson, southwestern Jack County, where at the present time approximately 70 operations are under way. During the year considerable new production of 39°-40° gravity oil was developed from lenticular sands in the Strawn at an approximate depth of 2,975 feet. The Rathke field, situated north of the town of South Bend, south Young County, was further developed during 1936. Production is from a Smithwick sand, the Caddo limestone, of the Smithwick section, and from upper Marble Falls sand and sandy limestone, all of Bend age, from depths of 3,600 to 4,000 feet. The oil is 38° gravity. In Shackelford County the Bluff Creek field was extended, and in Jones County new extensions were made to the Leuders and Hawley fields, all producing from the Cisco. A new area of Cisco production was discovered in Jones County about 2½ miles east of the Hawley field. In western Hamilton County a new gas area was discovered with production from Bend limestone. Scattered new production was developed in several additional counties throughout the west-central and north Texas districts. Early in 1936 interest was stimulated in Montague, Cooke, and Grayson counties, Texas, by the discovery of oil in limestone beds of Simpson age in the Fox field, Carter County, Oklahoma. Considerable seismograph work and leasing were done in this area of Texas. Two deep tests were drilled in search of Simpson production, and a third is now drilling. On development of production in the Altus field, Jackson County, Oklahoma, and, later in the year, when deep drilling disclosed the presence of Simpson in Tillman County, Oklahoma, interest gradually spread westward to northwestern Wichita, northern Wilbarger, Foard, and Hardeman counties, Texas, where considerable seismograph work has been done and is still under way. The oil and gas field is situated on the Amarillo uplift, petroleum accumulation being found in the Panhandle lime and granite wash of Lower Permian and Upper Pennsylvanian age. In general, gas production is confined to the structurally higher part of the field and oil production is found lower on the structure and principally on the northern flank. End_Page 1015------------------------------ Fig. 1. Late Paleozoic tectonic features in south-central United States. Width of area shown in map, approximately 1,400 miles. Redrawn and revised by Sidney Powers. From W.A.J.M. van Waterschoot van der Gracht, Permo-Carboniferous Orogeny in South-Central United States, Bull. Amer. Assoc. Petrol. Geol., Vol. 15, No. 9 (September, 1931), Fig. 1, p. 993. End_Page 1016------------------------------ A northwestward extension of production occurred in the Stinnett area, west-central Hutchinson County, where nine oil wells have been completed and several tests are drilling. Recently, a gas well was completed in northern Hansford County directly south of the Oklahoma state line. Moore County was the scene of the larger part of new activity during 1936, as many old 10-year leases had to be developed, renewed, or dropped. Natural gas is the most important production in the county, with sweet gas in the southern part and sour gas in the northeastern. By Railroad Commission order only sour-gas residue from gasoline plants can be used in the manufacture of carbon black, with the result that the past year witnessed a great expansion of the natural-gasoline and carbon-black industry in Moore County to draw on the sour-gas reserve.

The Late-Glacial Stage of the Lea Valley (Third Report)

Shortly after the publication of the later of the previous papers on this subject, I discovered another exposure of the Late-Glacial deposits of the Lea Valley. It was found under rather unsatisfactory stratigraphical conditions, during some small secondary digging in a practically abandoned gravel-pit of large size. The sides of the pit are sloped down and overgrown, and in part built over, so that the stratigraphical relations of the deposit in question are obscure. The site is on the higher margin of the 50-foot, or Taplow, Terrace, immediately below the 100-foot contour, east of the New River, and north of the road which runs through Barrowell Green, between Winchmore Hill and Palmers Green, Edmonton. On the first visit, I noticed a bed of clav, about a foot thick, of which several yards could be seen. As it was clearly in place, and had been left as unprofitable during the digging, I took a sample home, and found it to yield seeds, but comparatively little vegetable debris apart from the seeds, so it was unusually easy to work for the purpose in hand. A few days later I spent an afternoon in the pit, washing out as much of the clay as I could in the time, and forwarded the results to the late Mr. Clement Reid. He sent me a preliminary list and statement, which were not intended for publication until the identifications had been checked; this work Mrs. E. M. Eeid & Miss M. E. J. Chandler have now