An Isopach Map and a Discussion of the Permian in Wyoming and Adjacent Areas

The accelerated post-war demand for petroleum products with resultant high prices and dwindling reserves has spurred producers to an extensive search for new fields and for ad­ditional production in known fields. Exploration and discov­ery is dependent on the collection and correlation of vast amounts of data both in the field and that found in liter­ature.

A Preliminary Study of the Ostracoda of the Big Snowy Group, Mississippian, of Montana.

In the field, samples were taken vertically and horizon­tally along the various outcrops in different sections of central and south-central Montana. At important localities the samples were taken about every half-foot verti­cally; in other sections they were taken every few feet.

Contact Metamorphism in the Highlands

On the southern margin of the Boulder Batholith, about twenty miles south of Butte in the Highland Mountains, there are many miles of contact between the igneous and sedi­mentary rocks. As two kinds of igneous rocks and many diff­erent kinds of sedimentary rock are present, it is an excell­ent place for the study of contact metamorphism.

The Pre-Jurassic Surface of Montana.

It has long been known that, prior to the deposition of Jurassic sediments, Montana was subjected to an intensive period of erosion. Mention of this may be found in numerous reports, especially those dealing with western Montana.

Report on the Ermont Mine Sec. 35, T. 6 S., R. 11 W., Beaverhead County, Montana

An examination of the Ermont Mine was requested by the owners, Messrs. J. R. Bowles and R. B. Caswell, to determine the amount and grade of ore developed, the advisability of constructing a mill at the present time, and to recommend future development work.

Areal Geology of the Post-Paleozoic Surface of the Northwest Plains

Probably most of the area included in this report has been ex­amined to some extent by oil geologists, and most, if not all, of the important domes have been discovered and surveyed thoroughly. In parts of the area, the bedrock is covered by glacial drift or alluvium materi­al, but it is reasonable to believe that no new domal structure will be found. This means that surface examination alone will be insufficient in locating new oil fields, so future prospecting will be dependent, to a great extent, on studies of sub-surface stratigraphy.

Fauna of the Three Forks Formation in Montana

The purpose of this paper is to identify and describe the fauna, correlate it with that of the Upper Devonian of other states, to note the geographic distribution, lithologic variations of outcrops, and to compare measured cross sections.

A Report of the Geology of the Golden Sunlight Mining District

This paper is a report of a geological survey made of an area of approximately fifty square miles lying Northeast of Whitehall, Montana, in the region of the Golden Sun­light Mine. The survey was made by a field party consisting of twenty-three members of the senior class of the Montana School of Mines.

A Geological Report on an Area Five Miles Southeast of Renova, Montana, and on an Area Seven Miles South of Jefferson Island, Montana

This trip was conducted to give those students working for their respective degrees an excellent opportunity to work under actual field conditions. A total of three weeks was taken to complete the required work. Two weeks were spent in the field gathering data, and making maps, and the last week was spent in the drawing room at the college preparing the final map.

A Study of the Concentration of a Low-Grade Manganese Ore from the Ennis District

The purpose of the investigation was to determine the most effective means of concentrating the manganese in the ore. The study was that of identification of the minerals present. This showed the presence of oxides of manganese and iron, and carbonates of calcium and manganese. Methods of investigation were planned to determined whether the ore could be concentrated effectively by gravity concentration methods. ­

Stratigraphic Studies of the Ordovician and Devonian Formations Throughout the Northwest Plains Area

As yet the knowledge of Ordovician and Devonian physiography in this vast northwest region remains almost a complete secret. Very little, in any, work has been done along this line with the exception of those areas where the various formations outcrop.

Upper Mississippian Faunas of Western Montana

The author has made a study of an assemblage of fossils from the Blacktail Range near Dillon Montana with the purpose in view of attempting a correlation of that group with the fauna of the Big Snowy Group. Fossils have also been obtained from a limestone formation in northwestern Montana and from four different areas in the Amsden formation in central and western Mont­ana.

Geologic Field Mapping in an Area Eight Miles North of Three Forks, Montana

The Three Forks are includes parts of Jefferson, Madison, Broadwater Pond Gallatin counties, Montana. Sedimentary formations lie at the surface nearly everywhere in the area, and the rugged surface topography has been developed through the folding and tilting of these formations and their dif­ferential erosion.

Insoluble Residues of the Lower Mississippian Limestones of the Madison Group

The correlation of non-fossiliferous drill samples is one of the difficult problems that is en­countered in sub-surface stratigraphy. In order to truly correlate a formation, it must have some dis tinctive features and have an areal persistence of these features. These requirements are probably met best by limestone.

Permeability and Porosity Studies of the Cut Bank Oil Sand

In studying the Cut Bank field and its numerous wells, it is found that dry holes are surrounded by producing wells, and also that the field as a whole is very irregular; water, oil, and gas zones in many cases following no definite pattern. In some instances, this phenomenon may be due to the lensing and thinning of the producing sands, but it is evident that this is not the only factor. There­fore, the controlling factors must be porosity and permeability.