General Statement The Summer Ranch and North Promontory Mountains have not been studied in detail geologically, although the surrounding mountains have been extensively investigated. Within the limits of this area, sedimentary rocks of Mississippian through Permian crop out. Sedimentary and volcanic rocks of Tertiary age are also exposed. Extensive Lake Bonneville deposits underlie the valleys and overlap the foothills. The purposes of this study are: (1) to describe the structure, stratigraphy, and geologic history of the area, (2) to prepare a geologic map of the area, and (3) to relate the stratigraphic features of this area to those of the surrounding region. Location of Area The area studied is bordered on the north by the Utah-Idaho state line and on the east by Blue Creek Valley. Utah State Highway 83 and Great Salt Lake form the southern boundary and Curlew Valley, south-southwest from Snowville, Utah, defines the western limit (Figure 1). The mapped area lies completely .within Box Elder County and covers a total of about 529 square miles. The Utah division of the Thiokol Chemical Corporation is located near the southeast corner of the mapped area. Field Work Initial field work was begun in August of 1960. Investigation of the 3 mapped area plus near-by areas was carried on continuously through September of that year and intermittently until June, 1961. Access roads are mainly unimproved but are passable by passenger car. Water is available at most of the ranches in the adjoining valleys and at several springs in the North Promontory and Summer Ranch Mountains. Structural and stratigraphic details were plotted on vertical aerial photographs in the field. Information was subsequently transferred to a topographic map at a scale of 1:62, 500, which was enlarged from a U. S. Geological Survey map, then traced on a transparent overlay. Stratigraphic sections were measured with a Brunton compass or with a steel tape. Previous Investigations No previous complete geologic investigation has been made of the area covered by this report. Various local features within the mapped area have been studied. Walter (1934, p. 178-195) describes the structural relations of the Hansel Valley earthquake of 1934. Additional investigation concerning the structure of Hansel Valley was conducted by Adams (1938). Tertiary stratigraphy of Cache Valley was studied by Adamson (1955). Adamson reported the occurrence of tuffaceous rocks, similar to those in Cache Valley, in association with basalt flows near Snowville, Utah. Smith (1953, p. 74) diagrams the southern limit of the Snake River basalt flows and showed that they covered the northern part of the area concerned in the present investigation.

The Bloomington Formation (~425 m thick) is a latest Middle Cambrian (~506.5-505 Ma), mixed, warm water, continental-shelf carbonate and fine-grained siliciclastic unit on the Cordilleran passive margin exposed in northern Utah and southern Idaho. Thicknesses of the Bloomington Formation at Calls Fort Canyon are 111 m in the Hodges Shale Member, 230 m in the middle limestone Member, and 84 m in the Calls Fort Shale Member. The Hodges Shale and Calls Fort Shale Members are shale dominated and represent outer detrital belt deposition. The Logan Canyon outcrop of the Hodges Shale Member shows an environmental change that may represent a transition form an open marine facies into what appears to be a lagoonal facies. The middle limestone member represents shallow marine carbonate deposition on the passive margin shelf. The Bloomington Formation has a low fossil abundance and diversity when compared to correlative units such as the Wheeler and Marjum Formations. There are, however, 10-50 cm thrombolite bioherms, associated with Girvanella oncoliths. These bioherms indicate a shallow-water carbonate facies that experienced a small flooding event that gives the bioherms time and proper conditions to build up. δ18O and δ13C results both show positive and negative shifts with δ13CVPDB values of 1.0 to -4.7 per mil and δ18OVSMOW values of -12.9 to -20.8 per mil. A negative δ13C excursion in the Hodges Shale may correlate to a similar excursion in the base of the Wheeler Formation that represents the DICE event. Lower and Middle Cambrian Formations in the Wellsville Range have been interpreted as being part of a second order transgressive system and containing third and higher-order cycles. The contact of the Hodges Shale Member and the underlying Blacksmith Dolomite represents a flooding surface and a sequence boundary, followed by a third order cycle. Flooding is indicated by shale deposits that overlie carbonates with a shallowing upward trend. High frequency fourth or fifth order cycles are expressed as laminated shale and thick-bedded limestones as well as thick packages of interbedded, thin limestones and shales. A PCA analysis of thin section point counts indicates that the limestone lithologies of all three members repeat throughout the entire Formation, suggesting cycles of relative sea level rise that cause repeating facies.

The structure of the western three or four miles of the Bear River range east of Logan, Utah, has many times been alluded to in papers written locally on Cache Valley and the related ranges. There has not however, ever been, to the author's knowledge, an investigation made of this portion of the range for the express purpose of determining its exact structure. Although the area specifically covered by this present investigation is greatly inadequate to base the whole west range structure on, the author believes that the facts brought to light by the specific study of this area, added to the facts already known of the rest of the range, will give a clearer and more comprehensive interpretation of the whole western Bear River range front. It was with this purpose in mind that the present investigation was made. The original outline for the study included an investigation of the paleontology of the section. It was found however, after a few weeks study in the field, that the fossils in the local section are far too scarce for any comprehensive study in the present investigation. The study herein described then will be found to refer to paleontology only where it is necessary or where fossil horizons were found advantageous over lithologic units for mapping of formations. The section represented here has several times been studied in part. With a study of these investigations, it was found that there was enough lithologic difference in most of the sections to make possible local correlation and mapping on that basis. In order to make the present paper more thorough and complete it seemed advisable to branch out from the specific area in a few cases and investigate other parts of the valley and range for further insight.into some of the problems confronted on the area. It was also found necessary to make a rather complete study of the literature of related areas.

The Ordos basin rests upon the North China Block and is one of the largest sedimentary basins in north China, with more than 15 km of Phanerozoic strata. Published estimates suggest that over 2000 m of carbonates and lesser amounts of siliciclastics were deposited on the North China Carbonate Platform (NCCP) from the Lower Can1brian through the Middle Ordovician. However, lower Paleozoic facies successions and deposystems of northwestern Ordos basin remain poorly represented in western literature. This paper constrains depositional environments, lithologies, facies relationships and sea-level history of the northwestern part of the North China block (NCB) in an effort to further document the Early Paleozoic geologic history of western Ordos basin. New stratigraphic data come largely from measured sections in the Zhuozi Shan and Helan Shan in northwest Ordos basin. Strata in the mountains of northwestern Ordos are divided into eleven lithofacies assemblages, distinguished by lithology, stacking patterns and sedimentary structures. Lithofacies assemblages in northwest Ordos are grouped into four lithostratigraphic units that make up the composite type section. Unit A is dominantly composed of shale and mudrock lithofacies, Unit B is dominantly composed of thin-bedded lime mudstone and banded and bioturbated lime mudstone to wackestone, Unit C is dominantly composed of quartz sandstone and dolostone and Unit D is dominantly composed of fossiliferous packstone. These four units were observed in all lower Paleozoic sections of the Helan Shan and Zhuozi Shan. Deposition of Middle Cambrian through lowermost Lower Ordovician strata in northwest Ordos basin occurred on a storm-influenced, mixed siliciclastic and carbonate, shallow-water ramp. Lateral trends in quartz sandstone, paleokarsts, thrombolites and section thickness suggest that accommodation space increased to the south. The depositional architecture changed in the Middle Ordovician to a carbonate shelf environment. The sea-level history of northwestern Ordos shows transgression through the Late Can1brian, regression in the Early Ordovician, followed by a Middle Ordovician transgression, corresponding with North American sea level signatures. Lower Paleozoic sections in northwestern Ordos basin are broadly similar to those previously described in western literature. However, based upon stratigraphic data, shoreline trends of the NCCP model are proved inapplicable to northwestern Ordos. There is no evidence for lower Paleozoic tectonics such as aulacogen-controlled subsidence and platform tilting as described by previous workers. The sea-level history interpreted for northwest Ordos basin is more similar to North American curves than to the North China Carbonate Platform model, suggesting a eustatic control on lithofacies stacking patterns in northwest Ordos basin.

The Red Pine Shale (RPS; ~1120m), uppermost formation of the Neoproterozoic Uinta Mountain Group, Utah, is an organic-rich sedimentary succession that represents marine deltaic systems delivering mature sediment from the east and immature sediment from the north. Multiple data sets suggest regional climate and sea-level changes associated with changing organic carbon burial rates. Six facies identified represent wave-, tidal-, and river-influenced parts of the distal prodelta to delta front. The shale facies is interpreted as distal prodeltaic deposition in a marine environment. The concretion facies is interpreted as prodeltaic deposition to distal prodelta. The shale-sandstone facies represents suspension settling with dilute density currents in a proximal prodelta to delta front environment. The slump fold facies was deposited on the proximal prodelta or delta front. The sandstone facies represents deposition on the delta front and shows marine- and river- influences. The pebbly sandstone facies is representative of a delta front environment. C-isotope values from this shale range from -29.46 / to -16.91 / PDB and TOC from 0.04% to 5.91%. Combined H/C, TOC, and local-regional isotopic correlations suggest that these values are representative of C-isotope composition of Neoproterozoic seawater. The composite C-isotope curve for the RPS is less negative values near the base, followed by a long decline to a thick interval of homogeneous lower values. Petrographic analyses reveal immature arkosic sandstone and mature quartz arenite populations. Detrital zircon data show an Archean population from the Wyoming Craton to the north and a mixed Proterozoic/Archean population from the east-southeast. Measured sections show north to south delta progradation with a proximal source to the north and a mature sediment source to the east. The composite section shows one low-order regressive cycle and ~11 high-order cycles. There is a relationship between C-isotope values, shale geochemistry, and lithostratigraphy. Less negative C-isotope values correspond with increased kaolinite and facies indicating higher sea-level. These relationships are seen in the correlative Chuar Group, Arizona, and a similar model is suggested for their origin: humid climate, high organic carbon burial rates, and high sea-level. This paper meets the requirements to revise the RPS as a formalized unit in accordance with the Stratigraphic Code guidelines.

The Middle Cambrian Spence Shale Member contains meter-scale, shallowing-up cycles (parasequences) and record approximately 360 ky of deposition. These meter-scale cycles are nested within transgressive systems tracts (TST) and highstand systems tracts (HST) which reflect different stages of a lower-order, higher-magnitude sea-level excursion. Fossil assemblages are located in stratigraphic positions within the Spence Shale Member that can be predicted on the basis of sequence architecture. The cycle architecture, taphonomy, and geochemistry of the Spence parasequences confirm synthetic sections and theoretical models of meter-scale cycles developed in other studies. Delineation of meterscale cycles, based on taphonomic and sedimentologic criteria, allows high-resolution (100-500 ky) correlation. This study also documented the Cambrian existence of the Tooele and Arco Arches and aided in further understanding paleoenvironmental conditions within the Spence Shale Member.

The study area lies in southwest Douglas County 5 kilometers south from Camas Valley and is accessible by state highway 42. The purpose of the study was to map the geology at a 1:31,250 scale, determine the stratigraphy, study the petrology of the formations, and determine the provenance within a tectonic setting.

The Clackamas River drainage within the western Cascade Range is approximately aligned with a northwest trending lineation defined by the Portland Hills and the Brothers Fault zone. This area is occupied by an extensive Columbia River Basalt sequence that is deeply incised by the Clackamas River and its tributaries. Two major basalt units of the Yakima Basalt Subgroup, including the Grande Ronde Basalt and the Frenchman Springs Member of the Wanapurn Basalt, are distinguishable in a 515 meter to 550 meter accumulation. Of particular interest is the presence of five trending right-lateral strike-slip faults is consistent with a stress model of north-south compression and east-west extension.

Within the thesis study area Spencer Formation arkosic/arkosic lithic sandstone lithofacies of Narizian age crop out in a sinuous north-northwesterly band from the Corvallis area into the Henry Hagg Lake vicinity ten kilometers southwest of Forest Grove, Oregon.

Evidence of the Cretaceous-Paleogene (K-Pg) extinction can be seen across the Mississippi Embayment, however research examining the K-Pg boundary in the state of Mississippi is lacking. The objective of this study addresses how macrofauna changed across the K-Pg boundary in Oktibbeha County, Mississippi and subsequent comparison to other Early Paleogene and Late Cretaceous benthic marine macrofaunal localities. Comparison included previously collected material as well as specimens collected during this study in order to reconstruct the biological community living on the seafloor in the earliest Paleocene Mississippi Embayment. The primary fauna present after the K-Pg extinction was mainly composed of small suspension and deposit feeding oysters and clams as well as carnivorous gastropods. New Paleocene fauna and survivor species exhibited drastically smaller body sizes than organisms in the Cretaceous; postulated to be due to a relative decrease in primary producers and environmental nutrients.