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Geology And Petroleum Potential Of The Hay Creek Anticline, North-Central Oregon, Stephen I. Wareham Aug 1986

Geology And Petroleum Potential Of The Hay Creek Anticline, North-Central Oregon, Stephen I. Wareham

Loma Linda University Electronic Theses, Dissertations & Projects

For many years it has been reported that the core of the Hay Creek Anticline exposes metamorphic rocks of Paleozoic or Mesozoic age. On closer study it was found that these rocks consist of only slightly metamorphosed black to dark grey siltstones and sandstones with less abundant chert pebble conglomerate and recrystallized limestone. The sequence is here informally named "Hay Creek Formation." Calcareous nannofossils recovered and identified from the limestone yielded an age of early to middle Eocene.

The depositional environment of the "Hay Creek Formation" is interpreted to be a submarine turbidite fan. Siltstones were deposited as pelagic rain …


A Structural Investigation Of A Basement-Involved Thrust System In Southern Sphinx Mountain Quadrangle (Madison Range) Southwestern Montana, Jeffrey Scott Brown Aug 1986

A Structural Investigation Of A Basement-Involved Thrust System In Southern Sphinx Mountain Quadrangle (Madison Range) Southwestern Montana, Jeffrey Scott Brown

Masters Theses

The Madison Range is the eastern limb of the Laramide Rocky Mountain foreland Madison-Gravelly Arch. The main segment of the Madison thrust system in the map area is the basement-involved Scarface thrust which dips westward, trends north-northwest, and places Archean rocks onto an overturned footwall of Cambrian through Cretaceous rocks. Foliation of Archean rocks in the footwall is folded with overlying sedimentary rocks.

The Shedhorn Mountain thrust splays from the Scarface thrust. It is exposed north and south of the Shedhorn Mountain anticline, but is blind beneath it. The Taylor fault, an east-dipping back thrust, is inferred to be associated …


Stratigraphic And Sedimentologic Analysis Of The Middle Devonian Filer Sandstone, John Charles Rodwan Aug 1986

Stratigraphic And Sedimentologic Analysis Of The Middle Devonian Filer Sandstone, John Charles Rodwan

Masters Theses

The Filer Sandstone, a multistory assemblage o£ lenticular sand bodies, is a member of the Middle Devonian Amherstburg Formation of the Detroit River Group in the subsurface of the western and central portion of the Michigan Basin. It is distinguished from the reworked eolian and nearshore marine sand facies of the underlying Sylvania Sandstone by recognition of its barrier island facies relationships and stratigraphic position within enclosing carbonates unique to the Amherstburg Formation. Lithologically, the Filer ranges from a fine-grained, carbonate-cemented, supermature quartzarenite at its upper shoreface facies, to a texturally-inverted sandy carbonate at its lagoonal facies. Facies distribution was …


Tephrostratigraphy Of The Middle Eocene Chumstick Formation, Cascade Range, Douglas County, Washington, Matthew John Mcclincy Jul 1986

Tephrostratigraphy Of The Middle Eocene Chumstick Formation, Cascade Range, Douglas County, Washington, Matthew John Mcclincy

Dissertations and Theses

This study outlines the ash (tuff) bed stratigraphy (tephrostratigraphy) in the middle Eocene Chumstick Formation of central Washington. The tuff beds provide local marker beds enabling interpretation of the stratigraphy and structure of the formation. The chemical signature of these units provides the basis on which the units can be traced over broad areas in the basin of deposition. Correlations of tuff beds were obtained over distances of 41 km.

The tephrostratigraphy of the Chumstick Formation consists of nineteen tuff marker beds. Seventeen of these units are chemically characterized in this study. Ten elements were used to fingerprint these tuff …


Long-Term Tributary Adjustments To Base-Level Lowering, Northern Rio Grande Rift, New Mexico, Keith Irvin Kelson Jul 1986

Long-Term Tributary Adjustments To Base-Level Lowering, Northern Rio Grande Rift, New Mexico, Keith Irvin Kelson

Earth and Planetary Sciences ETDs

ABSTRACT

Late Cenozoic (post-3.6 Ma) entrenchment of the Rio Grande in northern New Mexico formed a gorge over 200 m deep and induced different types of fluvial adjustments on two adjacent tributaries. Rio Hondo (drainage area 181 km2 ) has a concave-up long-profile and flows in a narrow valley containing six Quaternary strath terraces with parallel long-profiles grading to the Rio Grande. In contrast, Rio Pueblo de Taos (drainage area 1080 km2 ) has a convex-up long-profile and flows in a wide valley containing four strath terraces which do not grade to the Rio Grande. Although smaller in drainage area, …


A Model For Assessing The Visual Resources Of River Basins As An Aid To Making Landuse Planning Decisions, Thomas J. Nieman, Diane S. Meshako, David Walters, Molly M. Davis, Cindy C. Elliot Jul 1986

A Model For Assessing The Visual Resources Of River Basins As An Aid To Making Landuse Planning Decisions, Thomas J. Nieman, Diane S. Meshako, David Walters, Molly M. Davis, Cindy C. Elliot

KWRRI Research Reports

The visual quality of a river basin and its associated properties can be identified, evaluated and integrated into the landscape planning process. The model developed provides a quantitative methodology for determining visual quality on the basis of available Geographic Information System factors. These factors are utilized to develop the preference attributes, COLOR, FORM, TEXTURE and LINE, which are associated with the assessment of visual quality. The preference attributes are then combined through a decision making process into a continuum of DISTINCTIVE, GOOD, AVERAGE and MINIMAL visual quality and is expressed digitally in map format. By providing visual quality information in …


Benthic Foraminifera And Paleoenvironments Of The Arcola Limestone Member Mooreville Formation (Campanian) In Eastern Mississippi And Western Alabama, Julia K. Palmer Jul 1986

Benthic Foraminifera And Paleoenvironments Of The Arcola Limestone Member Mooreville Formation (Campanian) In Eastern Mississippi And Western Alabama, Julia K. Palmer

OES Theses and Dissertations

Eighty-one species of benthic foraminifera have been recovered from chalky marls of the upper Mooreville Formation including the Arcola Limestone Member, and the basal Demopolis Formation located in five sections in east-central Mississippi and west-central Alabama. These species have been described and seventy-nine illustrated. Analysis of the environmental or depth preferences of abundant species together with planktonic percentages and benthic species diversity, indicates that the chalky marls were deposited in a broad shallow shelf sea (subtidal conditions less than 100m) greatly influenced by open ocean conditions. The benthic assemblage is composed of a mixture of typically neritic and bathyal species …


Groundwater Levels In Nebraska, 1985, Michael J. Ellis, Darryll T. Pederson Jul 1986

Groundwater Levels In Nebraska, 1985, Michael J. Ellis, Darryll T. Pederson

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Arnoldia Kuesii, A New Juvenile Fernlike Plant From The Lower Permian Of New Mexico, William D. Tidwell, Sidney Ash Jun 1986

Arnoldia Kuesii, A New Juvenile Fernlike Plant From The Lower Permian Of New Mexico, William D. Tidwell, Sidney Ash

Faculty Publications

A nearly complete juvenile fernlike plant is described here from Lower Permian rocks of New Mexico. The fossil consists of a horizontal rhizome with roots, a short thick upright aerial branch, and a tuft of dimorphic leaves. It is assigned to Arnodia kuesii gen. et sp. n. and appears to be the first juvenile fernlike plant known from the Upper Paleozoic. Abundant palynomorphs and other plant fossils associated with the fossil indicate that it is Early Permian in age.


Factors Affecting Epithecal Growth Lines In Four Coral Species, With Paleontological Implications, Jean-Luc Liénard Jun 1986

Factors Affecting Epithecal Growth Lines In Four Coral Species, With Paleontological Implications, Jean-Luc Liénard

Loma Linda University Electronic Theses, Dissertations & Projects

The number of epithecal (external) growth lines was surveyed over 124 days for Montastrea annularis growing at different depths (3.5 m to 61 m). There was a significant (P< .01) decrease in the number of lines with depth. Although the linear regression is significant, there is evidence for a logarithmic or quadratic relationship, and more data from greater depths are needed to determine which of these gives a better fit.

The number of growth lines formed during light-dark cycles of 16, 24 and 32 hours were compared for M. annularis, M. cavernosa, Porites astreoides and Tubastrea aurea. The variability among colonies from the same species was in many cases more significant than that among light treatments. This is a serious problem for anyone counting lines in corals, especially from a few specimens; therefore conclusions based on such counts seem hazardous on …


The Engineering Geology Of The Fountain Landslide, Hood River County, Oregon, Susanne L. D'Agnese May 1986

The Engineering Geology Of The Fountain Landslide, Hood River County, Oregon, Susanne L. D'Agnese

Dissertations and Theses

The Fountain Landslide located along I-84, five kilometers east of Cascade Locks, Oregon has moved periodically for over thirty years. Aerial photographs taken prior to recorded movement of the landslide show the headscarp of a large preexisting landslide. In 1952 a cut was made into the toe of the landslide to straighten Highway 30. The recorded movement history begins at this time. Stabilization procedures in the late 1950's focused on dewatering the slide mass. Movement had nearly stopped by 1957. A deeper cut was made into the toe of the landslide in 1966 to widen the highway to the four-laned …


Dynamic Deformation Of Volcanic Ejecta From The Toba Caldera: Possible Relevance To Cretaceous/Tertiary Boundary Phenomena, Neville L. Carter, Charles B. Officer, Craig A. Chesner, William I. Rose May 1986

Dynamic Deformation Of Volcanic Ejecta From The Toba Caldera: Possible Relevance To Cretaceous/Tertiary Boundary Phenomena, Neville L. Carter, Charles B. Officer, Craig A. Chesner, William I. Rose

Department of Geological and Mining Engineering and Sciences Publications

Plagioclase and biotite phenocrysts in ignimbrites erupted from the Toba caldera, Sumatra, show microstructures and textures indicative of shock stress levels higher than 10 GPa. Strong dynamic deformation has resulted in intense kinking in biotite and, with increasing shock intensity, the development in plagioclase of planar features, shock mosaicism, incipient recrystallization, and possible partial melting. Microstructures in quartz indicative of strong shock deformation are rare, however, and many shock lamellae, if formed, may have healed during post-shock residence in the hot ignimbrite; they might be preserved in ash falls. Peak shock stresses from explosive silicic volcanism and other endogenous processes …


Structural Geology Of The Central Part Of Clarkston Mountain, Malad Range, Utah, Douglas A. Green May 1986

Structural Geology Of The Central Part Of Clarkston Mountain, Malad Range, Utah, Douglas A. Green

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The central part of Clarkston Mountain is located in northcentral Utah in the southern part of the Malad Range. It is northwest of Clarkston, Utah. The mapped area measures 2.5 mi. in the north-south direction and 6.5 mi. in the east-west direction. It is within the Basin and Range Province.

The Ute Formation of Middle Cambrian age is the oldest exposed stratigraphic unit. Other Cambrian units, in ascending order, are: Blacksmith Formation, Bloomington Formation, Nounan Formation, and St. Charles Formation. These units consist predominantly of limestone, dolostone, and shale. Units of Ordovician age include the Garden City Formation and the …


Diagenesis And Water Chemistry Of The Woodbine Group In The East Texas Basin, Helmuth Victor Wuerch May 1986

Diagenesis And Water Chemistry Of The Woodbine Group In The East Texas Basin, Helmuth Victor Wuerch

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Petrographic and SEM study of flu vial-deltaic sections of the Woodbine Group in the East Texas Basin indicates that authigenic mineral suites are controlled, in part, by the presence of organic-rich matrix.

During early, precompaction diagenesis, organic matter supplied the metabolic fuel required by sulfate-reducing bacteria to reduce sulfate in depositional waters ultimately to pyrite. With burial the sulfate supply was ultimately exhausted, and bicarbonate activity thereafter controlled the precipitation of siderite and Fe-calcite.

Matrix material supplied the components and reaction sites for the most import ant porosity-occluding reaction: kaolinite --> Fe,M g chlorite. Matrix physically inhibited the growth of …


Petrology Of The Late Proterozoic(?) - Early Cambrian Arumbera Sandstone And The Late Proterozoic Quandong Conglomerate, East-Central Amadeus Basin, Central Australia, Johnnie O. Phillips May 1986

Petrology Of The Late Proterozoic(?) - Early Cambrian Arumbera Sandstone And The Late Proterozoic Quandong Conglomerate, East-Central Amadeus Basin, Central Australia, Johnnie O. Phillips

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Throughout the James Ranges and Gardiner Range the Arumbera Sandstone forms prominent strike ridges with distinctive dark reddish slopes and pale red to orange-white cliffs. Because of their lithologic and stratigraphic similarities, the names Eninta and ''Quandong" for these units should be suppressed in favor of the name of Arumbera Sandstone, which has precedence. The stratigraphic and lithologic differences observed between the Quandong Conglomerate in the type locality and the Arumbera Sandstone in the study area suggest that these units are not equivalent. Similarites with the Areyonga Formation suggest the Quandong Conglomerate could be part of the Areyonga Formation.

Lithofacies …


The Surficial Geology And Neotectonics Of Hansel Valley, Box Elder County, Utah, Robert M. Robison May 1986

The Surficial Geology And Neotectonics Of Hansel Valley, Box Elder County, Utah, Robert M. Robison

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Hansel Valley, located at the north end of the Great Salt Lake in Box Elder County, Utah, has exposures of the lacustrine sediments of the Little Valley, Bonneville, and Gilbert lake cycles. A 1:50,000 scale map was constructed of the surface geology. Although no trenches were dug for this study, about 240m of logs were compiled in an arroyo in lake bottom sediments. Sediments from at least three lake cycles were found in this gully: 1) compact bottom deposits from the Little Valley cycle; 2) bottom sediments from an intermediate cycle (the Hansel Valley cycle); and 3) beach gravel and …


Sedimentological And Foraminiferal Characterization Of A Holocene Island Slope (130-240m), North Jamaica, Craig V. Nelson May 1986

Sedimentological And Foraminiferal Characterization Of A Holocene Island Slope (130-240m), North Jamaica, Craig V. Nelson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Recent carbonate sediments from (133-236m) on the northern Jamaican island slope are significantly different from shallower reef zones (l-70m) in grain constituents, textural parameters, and foraminiferal assemblages. The island slope sediment is dominated by coral fragments, calcareous algae, Halimeda plates, and foraminiferal tests. The sediment is characteristically poorly-sorted, nearly-symmetrically skewed, and mesokurtic, with a mean grain size in the fine sand range. Mineralogically, the sediment is predominantly aragonite (66%) and high-Mg calcite (22%), with some calcite (8%), and minor amounts of clays and other insoluble minerals (4%).

Q-mode cluster analyses of sediment constituents, textural parameters, and foraminiferal species and larger …


Hydrogeology Of Water-Quality Monitoring Transects In An Irrigated Area Of The Eastern Sand Hills, Nebraska, Dennis R. Lawton May 1986

Hydrogeology Of Water-Quality Monitoring Transects In An Irrigated Area Of The Eastern Sand Hills, Nebraska, Dennis R. Lawton

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


The Geology And Hydrothermal Alteration Of The Bear Creek Butte Area, Crook County, Central Oregon, Richard Matthew Wilkening Apr 1986

The Geology And Hydrothermal Alteration Of The Bear Creek Butte Area, Crook County, Central Oregon, Richard Matthew Wilkening

Dissertations and Theses

The Eocene Clarno Formation, the Oligocene John Day Formation and basalts of the High Lava Plains are exposed in the Bear Creek Butte area in Central Oregon. In this area the Clarno Formation can be divided into a lower sequence composed of intermediate lava flows with intercalated mudflows and volcaniclastic sediments and an upper sequence of rhyolite and basalt flows and felsic ruffs. Separating the two units is a well developed saprolite. The change from intermediate to rhyolite-basalt volcanism reflects a change in the tectonic environment of the Cascade volcanic arc from compression to relaxation as subduction of the Farallon …


Transient Electromagnetic Sounding For Groundwater, David V. Fitterman, Mark T. Stewart Apr 1986

Transient Electromagnetic Sounding For Groundwater, David V. Fitterman, Mark T. Stewart

Geology Faculty Publications

The feasibility of using the transient electromagnetic sounding (TS or TDEM) method for groundwater exploration can be studied by means of numerical models. As examples of its applicability to groundwater exploration, we study four groundwater exploration problems: (1) mapping of alluvial fill and gravel zones over bedrock; (2) mapping of sand and gravel lenses in till; (3) detection of salt or brackish water interfaces in freshwater aquifers; and (4) determination of hydrostratigraphy. These groundwater problems require determination of the depth to bedrock; location of resistive, high-porosity zones associated with fresh water; determination of formation resistivity to assess water quality; and …


Facies Development And Porosity Relationships In The Dundee Limestone Of Gladwin County, Michigan, Eric Lee Montgomery Apr 1986

Facies Development And Porosity Relationships In The Dundee Limestone Of Gladwin County, Michigan, Eric Lee Montgomery

Masters Theses

The Devonian of the Michigan Basin was a time of transgressive seas and extensive carbonate deposition including coral and stromatoporoid buildups. Deposited during the Middle Devonian, the Dundee Limestone represents deposition in subtidal, intertidal, and restricted environments. The Buckeye Oil Field, located in south-central Gladwin County, is a combined stratigraphic and structural carbonate trap which produces from a series of intertonguing patch reefs, fringing sand bodies, and "intertidal island" fenestral zones. The major reef building organisms include stromatoporoids, corals, calcareous algae, brachiopods, and crinoids, with the stromatoporoids providing the major framework. The patch reef facies is composed of massive stromatoporoid …


The Provenance Of The Jacobsville Formation Of The Upper Peninsula Of Michigan Through A Petrographic Study, David Walter Lindsay Apr 1986

The Provenance Of The Jacobsville Formation Of The Upper Peninsula Of Michigan Through A Petrographic Study, David Walter Lindsay

Masters Theses

The Upper Keweenawan Jacobsville Formation source areas were mixed source terranes with dominant terrane types changing regionally in relative abundances of sediment contribution. Dominant source terranes were older sediments, including a weathered soil zone, Upper Keweenawan Freda Sandstone and other recycled sandstones; plutonic Precambrian basement rocks;. Middle Keweenawan Portage Lake Volcanics; and the chlorite to staurolite grade metamorphic rocks and iron ranges of Michigan’s upper peninsula.

Depositional environments of the formation's four facies types range from fluvial to deltaic/lacustrine. Sediments were in transport for a short distance, resulting in grain freshness and angularity, moderate sorting and preservation of unstable sediments. …


Petrography, Diagenetic History, And Development Of Porosity In The Richfield Member Of The Lower Middle Devonian Lucas Formation, Northeast Isabella County, Central Michigan Basin, Kevin James Sullivan Apr 1986

Petrography, Diagenetic History, And Development Of Porosity In The Richfield Member Of The Lower Middle Devonian Lucas Formation, Northeast Isabella County, Central Michigan Basin, Kevin James Sullivan

Masters Theses

The Richfield Member of the lower Middle Devonian Lucas Formation is represented in the subsurface of northeast Isabella County, Michigan as a 180-foot-thick sequence of Interbedded limestone, dolomite and anhydrite. Richfield lithofacies within the study area reflect deposition in a complex patchwork mosaic of evaporative supratidal, in tertid al, shoal, and subtidal environments.

The present variations in Richfield porosities were caused almost entirely by post-depositlonal diagenetic changes. The carbonate units have undergone pervasive dolomltlzation of mud matrix, leaching of allochems, and extensive anhydrite void -fillin g . The best porosity developments are associated with partial to complete dolomitizatlon of the …


An Evaluation Of The Effectiveness Of Bentonite As A Soil Additive For The Cover Material On The Kl Avenue Sanitary Landfill, Kalamazoo, Michigan, Neal J. Carey Apr 1986

An Evaluation Of The Effectiveness Of Bentonite As A Soil Additive For The Cover Material On The Kl Avenue Sanitary Landfill, Kalamazoo, Michigan, Neal J. Carey

Masters Theses

A principle objective of using bentonite as a soil additive is to reduce the permeability of a cover material, thus, inhibiting the infiltration of surface waters at landfill sites.

Twenty-two cores of the KL landfill were taken to obtain in-situ soil columns for testing. Coefficients of permeability were calculated for each soil column using the falling-head permeameter. Mechanical and hydrometer analyses were used for the grain size analysis. The methylene-blue test was employed to determine the actual percentages of bentonite present in each soil column. X-ray diffraction work was done on the clay fraction of each soil column to verify …


Lineament Analysis In The Richmond Triassic Basin Area Virginia: A Kinematic Model, Richard D. Lutz Apr 1986

Lineament Analysis In The Richmond Triassic Basin Area Virginia: A Kinematic Model, Richard D. Lutz

OES Theses and Dissertations

A lineament study from various sources (color-infrared U-2 photos, rectified drainage maps, and aeromagnetic maps) was conducted to develop a conceptual kinematic model for the Richmond Triassic basin area in Virginia. The lineaments were digitized and subjected to a computerized correlation package that compared the statistically significant peaks within 8 km2 grid cells. Spatially filtered significant 10° contoured trends exhibited a high correlation with mapped structures, outcrop patterns, diabase dikes, and aeromagnetic alignments, suggesting that they represent the surface expressions of the boundaries of subsurface structural domains. Structurally important lineament zones include NE-trending lineaments which segment the basin, NNW-trending …


Relationship Of Stream Drainage And Airphoto-Derived Lineaments To Basement Structures In The North Central Virginia Coastal Plain, William F. Mullen Apr 1986

Relationship Of Stream Drainage And Airphoto-Derived Lineaments To Basement Structures In The North Central Virginia Coastal Plain, William F. Mullen

OES Theses and Dissertations

A lineament study was conducted in the north central coastal plain of Virginia using five different data sources; color infrared photo images, rectified stream segments, bouguer gravity anomaly maps, aeromagnetic anomaly maps, and residual magnetic anomaly maps to determine the potential of aerial photographic analysis in the delineation of basement structural features beneath the sedimentary cover of the Virginia Coastal Plain.

Statistical analysis of 1602 airphoto lineaments and 2337 rectified stream segments produced 15 airphoto lineaments and 18 rectified stream segment lineaments in the north central Coastal Plain Province of Virginia. Azimuthal coincidence of these 33 lineaments determined that there …


Surface Sediment Composition And Distribution In Hillsborough Bay, Florida 1986, City Of Tampa Department Of Sanitary Sewers Bay Study Group Mar 1986

Surface Sediment Composition And Distribution In Hillsborough Bay, Florida 1986, City Of Tampa Department Of Sanitary Sewers Bay Study Group

Reports

Surface sediments were mapped to determine the approximate boundaries and percent areal coverage of "mud" in Hillsborough Bay. Depth recorder soundings along 29 transects were used in conjunction with sediment grain size analyses form 19 stations to produce a sediment map.


Paleocurrent Analysis Of The Cretaceous Mitchell Formation, North-Central Oregon, Craig A. Sandefur Mar 1986

Paleocurrent Analysis Of The Cretaceous Mitchell Formation, North-Central Oregon, Craig A. Sandefur

Loma Linda University Electronic Theses, Dissertations & Projects

Cretaceous sedimentary rocks of north-central Oregon previously referred to as the Hudspeth and Gable Creek formations and recently renamed the Mitchell Formation are potential petroleum source and reservoir rocks. Thus, determining their extent under the cover of Tertiary volcanics is of great importance to future petroleum exploration in the southern half of the Columbia Basin. The direction of sediment transport has been previously studied by several workers with contradicting results and conclusions. The primary objective of this research was to expand the paleocurrent analysis using both macro- and micro-fabric to provide additional evidence of sediment transport direction. This information allows …


Environmental And Physiological Effects On Water Use Of Cereal Crops, Joon Kim Mar 1986

Environmental And Physiological Effects On Water Use Of Cereal Crops, Joon Kim

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Biostratigraphy Of The Cowlitz Formation In The Upper Nehalem River Basin, Northwest Oregon, Neil B. Shaw Feb 1986

Biostratigraphy Of The Cowlitz Formation In The Upper Nehalem River Basin, Northwest Oregon, Neil B. Shaw

Dissertations and Theses

Examination of stream and roadcut exposures of the Cowlitz Formation allows the selection of measured representative sections, and collection of fossils, from an area roughly defined by the intersection of the boundaries of Clatsop, Columbia, Tillamook and Washington counties in Oregon. The study defines the features of the local environment of deposition, correlates sections to derive a composite columnar section, and develops a checklist of species for both microfossils and megafossils of the Cowlitz Formation.