East-west Line Research Articles

Development and performance of a triple-pass solar collector and dryer system

A new type of solar collector has been designed and tested. The design is compact, sufficiently simple and gives a high thermal performance. This paper deals with the design of a modular drying system consisting of three functional units, namely a triplepass flat plate air collector, a drying cabinet, and a dehumidification chamber. The flat plat collector is 190 cm long, 122.5 cm wide and 23.5 cm deep externally and incorporates two absorbers separated by about 6 cm. Air flows below the bottom absorber during the first pass, then in the opposite direction and finally through the air spaces between the glazing and top absorber plate into a mixing chamber and a drying chamber; the top air space is divided into two compartments with baffles installed to distribute the air over the collector surface. The drying cabinet has two wall collectors located on the east-west line to provide additional heat gain and trays spaced equally on spacers. The dehumidification chamber is a rectangular box fitted with three perforated trays containing the desiccant, silica gel. This is used to sustain the drying process during periods of low insolation. The results showed that the outlet temperatures ranged from 90 to 101°C on clear days and at velocities of up to 3.5 m s −1. Thermal analysis of the collectory yielded average efficiencies of 73–81%. There was a steep temperature gradient between the top compartment, where temperatures were quite high, and the bottom compartment, where temperatures were only 2–6°C above ambient. This helped to minimise heat losses to the environment. The thickness of insulation necessary to maintain the same level of heat loss was calculated and the cost involved shown to be much greater than the additional cost of providing a second absorber and the associated baffles. Results of the drying tests with rice paddy and yam slices showed that the system dried rice paddy at a layer density of 7.4 kg m −2 from 25.93% (w.b., wet basis) to 5.31% (w.b.) in 10 h and yam slices at a layer density of 5 kg m −2 from 64.90% (w.b.) to 10.66% (w.b.) in 31 h. The control experiment at prevailing ambient conditions required 2 days and 4 days, respectively, to attain the same moisture levels.

Recently Discovered Overthrusting Northeast of Llano Uplift Along Extension of San Marcos Platform: New Exploration Frontier in Central Texas: ABSTRACT

TJB Resources recently completed gravity, magnetotelluric, and seismic geophysical surveys in San Saba and Mills Counties north of the Llano uplift, west of the Ouachita Disturbed belt. Significant results show overthrusting has occurred 60-70 mi west of the Ouachita Disturbed belt. Earliest thrusting could have occurred in the Silurian-Devonian from south or southeast. Faulting reoccurs during Pennsylvanian Ouachita thrusting and again in the Late Cretaceous. The primitive Llano uplift buttressed the allochthonous rocks moving north and west. Magnetotelluric and gravity data indicate the Llano uplift is a separate and distinct isolated remnant or terrain, with numerous igneous intrusions reaching to great depths. Associated with this thrusting is a major tectonic northwest-southeast lineament located parallel to the termination of the Cretaceous rocks, outcropping on the western edge of Mills and Lampasas Counties. This lineament is documented by east-west seismic lines displaying a 0.3-sec displacement and farther southwest a 1.1-sec displacement. Paleozoic fossils were found near the surface trace of the northwest-southwest lineament as observed on the east-west seismic line. This area was previously mapped as Cretaceous. Surface inspection found Paleozoic rocks containing crinoids, spirifers, and rugose corals, with beds dipping to 45/sup 0/, contrasted with the N2/sup 0/ regional dip surroundingmore » the lineament area. Well-log correlations from Marble Falls to Ellenberger range from 350 to 600 ft from east to west near the Llano uplift. The 60 to 70-mi frontal edge of the thrusting provides potential hydrocarbon traps along a north to northeast trend from central Texas to Oklahoma.« less

Cookers for solar homes

Means of piping solar energy into kitchens were investigated. Two different solar cookers utilising the heat-pipe principle were designed, constructed and tested. A cooker utilising an east-west line focusing collector, designated Mecca-1, was developed for this purpose. The second cooker was a flat-plate heat-pipe cooker, Mecca-2. A single heat pipe in each cooker absorbed the energy at the collector, transported it into the kitchen and delivered it to an insulated oven at the condenser end. Various heating and boiling experiments conducted on the two cookers demonstrated the feasibility of the concept. It was found that the Mecca-2 cooker with triple glazing had a utilisation efficiency of up to 19 per cent and could boil 1 litre of water in 27 min for a solar insolation of 900 W/m 2.

Genetic Variation and Phenotypic Plasticity in Populations of Paterson's Curse (Echium plantagineum L.) In South-Eastern Australia

Natural populations of Echium plantagineum on an east-west line across south-eastern Australia were sampled on three occasions during the growing season, and seeds collected from individual plants in each population were grown in a common glasshouse. In another experiment seedlings of E. plantagineum were divided and clones from each plant were grown under two soil moisture regimes. Field populations differed significantly in all seven characters measured at all sampling dates but, with one exception, between-population differences were unrelated to five climatic indices. Glasshouse populations differed significantly in 15 of 27 characters; variations in some of these characters were related by regression analysis to one or more of the climatic indices. Clones grown under moisture stress flowered later, had proportionally wider leaves and were smaller than well watered clones. The data suggest that an ecocline has developed, or is developing, in E. plantagineum in south- eastern Australia in response to large-scale and long-term aspects of climate, although extensive genetic variation between individuals in each population was also observed. This species exhibits a great deal of phenotypic plasticity in response to localized environmental factors.

Tectonics and Sedimentation of Middle Proterozoic Belt Basin, and Their Influence on Cretaceous Compression and Tertiary Extension in Western Montana and Northern Idaho: ABSTRACT

The Belt Supergroup was deposited in an intracratonic basin, occupied during much of its history by alluvial aprons that sloped down to a landlocked sea. Belt rocks are here analyzed in terms of 13 types, descriptive taxa in which the metamorphic overprint is filtered out and the original sedimentary aspects are emphasized. The lower Belt records maximum transgression of the Belt sea, during which turbidite sand and pelagic mud were deposited in the central part of the basin, carbonate mud accumulated on its eastern margin, and coarse conglomerate accumulated along its fault-bounded southern side. The Ravalli Group records extensive alluvial apron/mudflat progradation from the south and west. The middle Belt carbonate, representing a second large transgressive eriod, is characterized by terrigenous-carbonate cycles in the eastern part of the basin and by turbidite sand and mud, derived from the west, in the deeper, locally slumped, western part of the basin. The Missoula Group represents a series of northwest-facing prograded alluvial aprons alternating with transgressive mudflat and shallow-water deposits. The Garnet Range Formation, near the top of the Missoula Group, represents incursion of open marine waters into the Belt basin. The Belt basin subsided as a group of at least four large crustal blocks, separated by three nearly east-west fault lines and a northwest-trending fault line. Differential subsidence of the blocks is recorded in abrupt thickness changes and soft sediment deformation along the fault lines. Cretaceous thrusting formed western and eastern thrust belts which are continuous across the blocks, but which are segmented and broken along the east-west lines. Tertiary extensional dislocations along the lines. End_of_Article - Last_Page 871------------

Williston Basin Seislog Study: ABSTRACT

This paper describes the results of Seislog® (trade name) processing and interpretation of an east-west line in the North Dakota region of the Williston basin. Seislog processing involves inversion of the seismic trace data to produce a set of synthetic sonic logs. These resulting traces, which incorporate low-frequency velocity information, are displayed in terms of depth and isotransit times. These values are contoured and colored, based on a standard stratigraphic color scheme. The section studied is located just north of a dual producing oil pool from zones in the Ordovician Red River and Devonian Duperow Formations. A sonic log from the Long Creek 1 discovery well was digitized and filtered to match the frequency content of the original seismic data. This allows direct comparison between units in the well and the pseudosonic log (Seislog) trace nearest the well. Porosity development and lithologic units within the lower Paleozoic stratigraphic section can be correlated readily between the well and Seislog traces. Anomalous velocity zones within the Duperow and Red River Formations can be observed and correlated to producing intervals in the nearby wells. These results emphasize the importance of displaying inversion products that incorporate low-frequency data in the search for hydrocarbons in the Williston basin. The accumulations in this region are local in extent and are difficult to pinpoint by using conventional seismic data or displays. Seislog processing and displays provide a tested method for identification and delineation of interval velocity anomalies in the Red River and Duperow stratigraphic sections. These techniques can significantly reduce risks in both exploration and delineation drilling of these types of targets. End_of_Article - Last_Page 290------------

A method for the display and analysis of transitional paleomagnetic data

Application of a simple coordinate transformation to data from polarity transition and excursion records renders a form of display having strong similarities, yet distinct advantages, over the use of virtual geomagnetic poles. Specifically, the procedure consists of a single rotation about the east‐west line so as to align the +z axis of the local Cartesian system with the normal polarity axial dipole field direction associated with the recording site at the time of the event. The method makes possible the redefinition of concepts relevant to transitional field studies in terms of vector directions, a more meaningful approach than the use of virtual poles when nondipole field components are significant. Visually, polar stereographic plots in (D′,I′) space present paleodirectional movement as if one were literally peering down the dipole direction. Analysis of individual transition records in this rotated directional space makes easy the determination of (1) the angular distance of a given paleodirection from that of the axial dipole field, (2) the number of strictly transitional directions contained within a given record, and (3) the degree of near‐sidedness or far‐sidedness of each paleodirection. In addition, the comparison of records from distant sites for the purpose of harmonic analysis can be accomplished without the need for additional normalization. Such comparison plots in (D′,I′) space display transitional data in a form strongly reminiscent of virtual geomagnetic poles plotted with respect to a common site longitude. Records of polarity transitions and excursions are presented which illustrate the utility of the proposed approach.

Teleseismic prospecting of lithospheric contrasts beneath the Pyrenees and Alps

The possibility of deriving the three-dimensional structure of the lithosphere by inversion of arrival times from distant earthquakes has previously been assessed using data from permanent seismic arrays1. Temporary emplacement of arrays in regions of key interest furnishes a practicable tool for investigating their structure2,3, but the data needed for resolving complex three-dimensional structures are difficult to collect. We have therefore selected here regions where cylindrical symmetry reduces the problems to two dimensions and where the geological structure of interest is likely to produce large, easily detectable, relative arrival time anomalies. In this respect the depth variation of an interface with a large velocity contrast such as the Moho, as it is known to exist on average perpendicularly to the axis of alpine mountain ranges like the Alps and the Pyrenees, is of interest. In the case of the Pyrenees, explosion seismology profiling on parallel east-west lines in the North Pyrenean Zone (NPZ) and the Palaeozoic Axial Zone (PAZ)4–7 provides evidence of an increase of over 15 km in Moho depth across the range. The variation in this depth beneath the North Pyrenean Fault (NPF)8, a feature clearly expressed at the surface in the east as separating the NPZ and PAZ, can be shown to be very sharp, occurring over approximately 5km. These results call into question the hitherto assumed smoothness of deep structure.

Geophysical evidence for the extension of the Variscan front on to the Canadian continental margin: geodynamic and palaeogeographic consequences

Summary Dextral transcurrent movement and thrusting induced by transcurrent movement have been identified along a roughly east-west line across the continental shelf NE of Newfoundland at approximately 52°N. The location of that boundary correlates well on a pre-Mesozoic fit of the North Atlantic with the terminus of the Variscan front on the European margin. Seismic reflection, refraction, gravity and magnetic data show a structural succession across the boundary that correlates with that across the front in Europe. This North American continuity of the Variscan front has subsequently acted as the locus for Mesozoic tectonics.

The economic foundations of East-West migration during the 19th century

An attempt is made to account for pattern of east-west migration often observed in United States during nineteenth century. Two possible explanations are discussed. One is that settlers sought to minimize distance traveled to new land and other is that latitude-specific investments in seeds and human capital induced migrants to move along east-west lines. An explanation for demise of east-west pattern in late 1800s is also developed. The analysis is based on published census data 1860 manuscript schedules of population and Mormon family-group records. The study indicates that the east-west pattern was attributable to an important extent to farmers who used seeds particularly corn that were adapted to a given latitude and to farmers who acquired latitude-specific skills....Incentives diminished and national migration patterns changed during 1800s as farmers learned about farming in different environments as settlement reached Great Plains and beyond and as agriculture declined in importance. (EXCERPT)

Depositional Environments of Tyler Formation in Fryburg and Rocky Ridge Area, North Dakota: ABSTRACT

The Tyler Formation in southwestern North Dakota is a regressive barrier-island system dominated by two environments: (1) lagoon and (2) barrier-beach complex. The barrier islands formed along an east-west line in Golden Valley, Billings, and Stark Counties. Thickening eastward (5 to 20 ft), a gradational, coarsening-upward sequence of very fine to medium-grained, well-sorted quartzose sandstone is developed in the Medora, Fryburg, and Green River fields. Where there is good development of a shoreline, massive fine-grained, well-sorted sandstones with discontinuous, wavy carbonaceous laminae (foreshore environment) overlie fine-grained, well-sorted, cross-laminated, and bioturbated sandstones (shoreface environment). Northward, several offshore sand bars developed in a predominantly shallow restricted sea, typified by medium-gray to grayish-black ripple cross-laminated argillaceous limestones and shales. On the south, in a landward direction, barrier-island sands interfinger with grayish-black carbonaceous lagoonal shales, coal, and mudstone marsh deposits and varicolored mudstone tidal-flat deposits. The sandstones present in the Rocky Ridge vicinity are characteristically medium grained and silty, and exhibit unidirectional cross-stratification. They are interpreted as channel deposits disecting a landward facies of the lagoonal environment. The upper Tyler Formation is a regressive sequence characterized by anhydritic mudstones, desiccation features, and local chickenwire anhydrites overlying dark-gray fossiliferous, argillaceous limestones and shales. End_of_Article - Last_Page 635------------

Seismic measurements in the southern Dead Sea

A seismic refraction profile and several seismic CDP reflection lines were recently occupied in the southwestern part of the Dead Sea. The seismic data, which are of good quality, give a clear picture of the structure of the area. The western flank of the rift comprises a series of step faults, downthrown to the east with a total throw of some 7 km at which depth the Cretaceous base of the post-Cretaceous fill is located. On the east—west lines the base of the fill dips to the east while on the north—south lines this complex dips to the south with a change in direction of dip being evident in the southern portion of this profile. The post-Cretaceous sediments reach a maximum thickness of 7 km but may be even thicker eastward near the main eastern rift fault. These sediments are gently folded, possibly due to differential compaction and are dislocated by small-magnitude adjustment faults. Lateral transition from bedded layers of salt in the graben fill to a diapir is clearly seen.

Studies of Natural Populations of Mus. vi. Sizes of Populations Inhabiting Corn Cribs in Southwestern Ontario

Theoretical studies concerned with genetic variability in natural populations have generally considered genetically effective population sizes ( N e ) of 104 or greater. This study shows that N e in some highly polymorphic populations such as those of the house mouse, Mus musculus , may be considerably smaller. The mouse populations considered inhabit corn cribs in southwestern Ontario and are polymorphic at a number of loci. They are ideal for this work because the entire population can be collected over a short period of time, and because the various cribs provide replicas of the same general microhabitat. The mean population sizes were 14.4 and 54.4 in the winter and summer, respectively. No correlation was observed between population size and crib size. N e , based on the mean numbers of mice observed in the winter and summer collections and the assumption that all mice are reproductively active, was approximately 20. This could be as high as 70 in some populations and as low as 10 in others. To determine factors that might affect population size, data were collected on 16 environmental variables. Stepwise multiple regression analysis indicated that four environmental variables, compass orientation of a crib ( P < 0.001), number of predators ( P < 0.01), distance from an east-west line ( P < 0.01), and distance from a north-south line ( P < 0.05) were significantly associated with population size. Based on the male:female ratio in the summer populations, only one crib appeared to be fully utilized by the mice. In this exception, a crib with a high population density, a deficiency of males suggested competition for territory.

Longitudinal characteristics of Pc5 magnetic pulsations

Data from an East-West line of magnetometer stations stretching approximately along 67° geomagnetic latitude from western Alberta (290° geomagnetic longitude) to western Quebec (350° geomagnetic longitude) in Canada have been used to study the longitudinal characteristics of Pc5 geomagnetic pulsations. This paper concerns the analysis of 3 days' data of relatively intense pulsational activity which occurred around the middle of October in 1976. The intensity variations of Pc5 activity on longitude and time clearly show that the activity is localized in longitude in the morning sector and confused in the afternoon sector. Pulsational activity in the morning sector for two of the events studied appears to be markedly enhanced across the dawn terminator and midway through the pre-noon quadrant. A study of the longitudinal phase variation indicates that the eastern stations lead in phase before noon and lag in phase after noon. This implies that the signals propagate away from noon toward the dawn-dusk meridian. A systematic reversal in the sense of polarization in the horizontal plane was observed when the line of stations rotated across noon. The polarization characteristics in the vertical planes of the events recorded by stations in eastern Canada between 318° and 350° geomagnetic longitude appear to be stationary with respect to time suggesting that the polarization characteristics of pulsations are influenced by geoelectric structures. The implications of these morphological features will be discussed.

Reservoir Description for a Surfactant/ Polymer Pilot in a Fractured, Oil-Wet Reservoir - North Burbank Unit Tract 97

Synthesis of information from cores, logs, waterflood experience, transient pressure tests, geologic studies, log-inject-log measurements, and tracers was used to provide a coordinated reservoir description for designing and controlling a surfactant/polymer flood in a fractured, oil-wet reservoir under active waterflood. Introduction The North Burbank Unit Tract 97 surfactant/polymer pilot in Osage County, OK, is a cooperative project operated by Phillips Petroleum Co. for 17 working-interest owners, with support from the U.S. DOE. Before the start of continuous injection and production in the pilot pattern in Dec. 1975, a comprehensive reservoir study was conducted, including coring, logging, transient pressure tests, oil saturation measurements, prior waterflood history, and a geologic study. These were supplemented, during preflush injection, by freshwater production behavior and radioactive tracer investigations.This paper reports the results of these studies and their synthesis into a working reservoir description, which has provided the basis for planning and operating the pilot during the past 42 months. Discussion of the pilot performance is presented elsewhere. General Characteristics of the North Burbank Reservoir The North Burbank reservoir is a large sand body deposited near the shore of the Cherokee Sea of Pennsylvanian age. Though originally thought to be a series of overlapping offshore bars, recent geologic study shows it to be of fluvial origin. The sand averages 42 ft (12.8 m) in thickness, with a porosity of 16.8% and permeability 50 md. The formation is rather heterogeneous, both vertically and areally. Additional heterogeneity is imparted by a strongly directional east-west jointing, or fracturing, which results in a preferential east-west movement of injected fluids. Another important feature is that the sand is strongly oil-wet. Tract 97 Waterflooding History The pilot reservoir in Tract 97 (Fig. 1) was part of the 1954 phase of waterflood development. Because of the preferential east-west flow, the 20-acre (8.09-ha) pattern was developed as a staggered line drive with like wells in east-west lines. Water breakthrough and oil production response occurred nearly simultaneously at each of the Tract 97 producers, requiring about 8 months on the average. Fig. 2 shows the performance of Well 97-06, a typical response. Careful investigation of well behavior at various points in time from start of injection to peak oil production gave inconclusive results. JPT P. 1647＾

Magnetic survey of Lake Kinneret-central Jordan Valley, Israel

A magnetic survey of Lake Kinneret (Sea of Galilee) was conducted on a 1 km grid of north-south and east-west lines. The results indicate that the margins of the lake are associated with large amplitude anomalies, while the centre is quite smooth. The largest anomaly, more than 500 nT, was detected in the vicinity of the entrance of the Jordan River into the lake. Its source is interpreted to be Late Cenozoic basaltic flows. The lake's margins are associated with faults, hot springs and magnetic anomalies. A broad magnetic anomaly trending east-northeast extends from Ginosar Valley into the lake through most of the lake's width. The distribution of basalt flows of different ages and the various structures of the magnetized layers are all contributing to the magnetic anomaly pattern.

Potentialities of Lunar laser range-differencing for measuring the Earth's orientation

Range differences, as derived by differencing simultaneously measured ranges from two stations to one and the same lunar reflector, are investigated regarding their capabilities for determining the orientation of the earth in an earth-moon reference system. Each pair of co-observing stations forms an observational unit (line) which is located preferably along a meridian or parallel. For a time interval which lasts from the instant of the first simultaneous observation of the most eastern line to the last observation of the most western line, assuming a reasonable observational rate and incorporating observations for which the zenith distance does not exceed 70 degrees, an analysis of variance shows that the pole position and the earth rotation can be computed independently of errors in the adopted lunar ephemeris and with at least measurement accuracy given a design which consists of two north-south lines being separated by 90 degrees and one east-west line. In the case of one north-south line the standard deviation of the meridional polar motion component does not exceed three times the measurement accuracy. As long as the stations are located within 10° to 15° in north-south or east-west direction the standard deviations of the parameters do not increase significantly, The lengths of north-south and east-west lines can vary between 60° to 80° and 40° to 60° respectively. The existing lunar ranging stations in Australia, Japan, Texas and Hawaii could be used to test the suggested method.

Settlements in a sao paulo shield tunnel : Sozio, L E Tunn Tunnlg, V10, N7, 1978, P53–55

The East-West line of the Sao Paulo, Brazil subway system includes about 3.5 km of shield tunnels in the downtown area, about 3 km being completed. The designers (Promon Engenharia S/A) were responsible for the settlement monitoring system, and the data collected was analysed and correlated with characteristics of the soil and the tunnelling methods used. The soil settlement troughs are compared with those predicted by the methods of R.B. Peck and E.J. Cording. The influence of different tail grouting techniques, additional settlements due to the release of air pressure in the tunnel and cases of building damage are described.

Rye, Suppression of Fall Armyworms and Associated Arthropods, Plains, 1977

Abstract The field of rye forage used for this test was growing under cool temperatures and adequate moisture in Faceville sandy loam and Greenville sandy clay loam. Treatments were applied at a height of ca. 5 ft with a Cessna Aquagon plane possessing 32 D-10 nozzles and flying 80 (high rate of oil) - 120 mph. They were applied with water (5 gal/acre) or crop oil (8.16 and 5.44 gal/acre) at 45 psi. Plots were 100 x 850 ft with a minimum of 75 ft of untreated rye between them. They were arranged as randomized strips in 2 blocks. Series of 50 sweeps with a 15 in. (in dia.) net were taken just to the north (2 series) and south (2 series) of an east-west center line in each plot. Samples were placed in plastic bags, frozen, and counted in the laboratory.

Successful Stimulation in the Cotton Valley Sandstone - A Low-Permeability Reservoir

Thorough evaluation of field results in the Cotton Valley sand resulted in a dependable, successful approach to stimulation. This paper presents a history of the development of this approach and verifies successes with case histories of Cotton Valley wells. Introduction The Cotton Valley sandstone, located in north-central Louisiana and East Texas, is an extensive, coastal strand-plain sandstone deposition. Formation permeability and porosity are very low and stimulation is necessary permeability and porosity are very low and stimulation is necessary in most Cotton Valley wells to obtain economic production. Because of the depth of the formation (8,000 to production. Because of the depth of the formation (8,000 to 12,000 ft) and the reservoir temperature encountered (230 to 280 deg. F), the choice of fracturing procedures is somewhat limited. During the past 3 years, much success has been obtained with hydraulic fracturing using moderately viscous, temperature-stable, aqueous gel systems. Recently, in wells where fracturing-fluid retention has been a problem, the use of low-surface-tension surfactants and problem, the use of low-surface-tension surfactants and carbon dioxide with the fracturing fluid has helped improve fracturing-fluid recovery after treatment and has provided encouraging stimulation results. provided encouraging stimulation results.After a thorough evaluation of field results in the Cotton Valley sand, a dependable, successful treatment has been developed. This paper provides a history of the development of this approach and verifies present successes with case histories of Cotton Valley wells. Geologic Description Since drilling activity began on a large scale in north-central Louisiana in the early 1950's, the presence of an extensive group of sand bodies called the Cotton Valley Group has been known. The geological deposition of the area became better defined as well-control information was obtained. As early as 1944, Swain was able to describe geologically the over-all deposition history of the group of Upper Jurassic sands known as Cotton Valley. Swain also described Upper Jurassic deposition in northeastern Texas. In 1954, Forgotson further described these sediments and added some changes to Swain's descriptions. More recently, Thomas and Mann further defined the depositional trend of the Cotton Valley. This description is still believed to be fairly accurate. A general map of the Cotton Valley deposits and areas of interest is shown in Fig. 1. The sand member is 500 to 600 ft thick and grades into a thinner marine deposition, dipping to the southwest. The main sand body pinches out to the north with an east-west line in southern Arkansas and becomes lenticular in eastern Louisiana. During Late Jurassic time, the coast that bordered the Gulf of Mexico extended east and west across southern Arkansas. Parallel with the coast line, a long-shore barrier island in northern Louisiana separated a coastal lagoon in northernmost Louisiana from the open Gulf on the south. A delta that was formed by the ancestral Mississippi River in northeastern Louisiana and adjacent Mississippi supplied sand to the long-shore barrier island. The Late Jurassic coastal features are reflected clearly in the composition of the rock of the Cotton Valley Group. A well log showing "typical" Cotton Valley deposition is shown in Fig. 2. JPT P. 1267