Attempted Proofs of the Differentiation of Magmas by Syntexis

This investigation was an effort to obtain proof of the much disputed principle that most of the observed mag­netic differentiations have been due to the assimilation, or syntexis, of the intruded country rocks.

A Preliminary Study of the Micro-Fauna of Certain Paleozoic Formations of Montana

The study of the micro-fauna of Montana formations has been almost entirely neglected. Because the petroleum industry of this state has not felt the necessity for using micro-paleontology in its sub-surface correlations, the science has been but little used. The Montana Power Company has had an examination made of some of its well cuttings by a competent micro-paleontologist who found some foraminifera in Mesozoic sediments. However, no investiga­tions have been made to determine the presence and character of the micro-fauna of the Paleozoic formations of Montana.

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.

Foraminifera from the Colorado Shale of North-Central Montana

The use of foraminifera in the determination of geologic age, and in the correlation of strata, is one of the most important techniques in oil field stratigraphic studies. The petroleum industry in many regions relies on these microscopic life forms to determine the positions of oil-bearing horizons and to determine the tops of beds. In northern Montana the Colorado group of strata, a series of about 2,000 feet of dense, dark similar shales, is known to contain foraminifers.

Geology and Ore Deposits of the Golden Era and Goldfinch Mines, Argenta Mining District, Montana.

This report includes the results of geological investigation of a small area in the northern part of the Argenta mining district. Approximately two square miles were mapped. The underground working of the three mines only were accessible: the Goldfinch. Golden Era, and Mayday mines.

Montana Oil Fields

Since the discovery of oil in Montana in1916, the petroleum industry has advanced to a point where over 5,000,000 barrels of oil worthover $6,500,000 has been produced in each of the three past years (1936, 1937, and 1938).

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.

Ground Water in the Lake Basin Field and Adjacent Area

This thesis consists of studying the stratigraphic and structural features of the Lake Basin Field and an adjacent area with special emphasis upon the ground water conditions present.

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.

Stratigraphy and Paleontology of the Eagle Formation in Montana and Adjacent Areas

A conspicuous two hundred and fifty foot sandstone of central Montana, known as the Eagle Formation, constitutes part of the some five thousand feet of Cretaceous sediments in the state. It stands out in steep cliffs which stretch for many miles in the outcrop area from Wyoming to Canada.

Helena and Ennis Talc Deposits

The purpose of this report is to collect geologic data concerning two Montana talc occurrences at Helena and Ennis and to offer some explanation as to their origin. The two deposits cited are in somewhat similar lithologic settings and both possess the same mineralogical and structural features. Because of this similarity only the Helena deposit is covered in detail.

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.

Report of Investigation on the Physical Characteristics of the Oil Sands from the Cut Bank Field, Montana

The purpose of this research was to study the physical characteristics, mainly, porosity and permeability of the oil sands from the Cut Bank field, Glacier County, Montana. In so doing, a better understanding of the relation­ship of these physical characteristics to one another and to the pool itself could be obtained.

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.

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.