The present study is concerned with the description and petrogenesis of a group of basic and ultrabasic intrusive rocks in the District of Cochrane, Ontario. It includes descriptions of localities where exposures are good or considered to be petrogenetically significant and petrographic descriptions of the intrusive rocks. Comparisons are made with other basic and ultrabasic rock occurrences.

This thesis describes the design, construction and operation of an apparatus for experimentation with small, cylindrical samples under conditions of high temperature and pressure in the presence of fluids. It is also possible to deform the sample while subjected to these "hydrothermal" conditions by developing a differential which can produce either shearing or tensional phenomena. Both open and closed systems can be employed. [...]

The general geology of an area of 50 square miles comprising the western half of La Motte township, Abitibi County, Quebec, is described. Peridotites and dunites occur as sills in Early Precambrian volcanic and sedimentary rocks. The belts of rock constitute part of the northern limb of a major anticlinorium. Granitic rocks of the Preissac-La Motte-La Corne batholithic complex probably derived from a common magma chamber occupy about 75 per cent of the map-area. The younger muscovite- and biotite-bearing quartz monzonite masses contain a higher percentage of potash feldspar than the biotite granodiorite masses.

The rapid depletion of iron ore reserves in the Lake Superior region, coupled with increased blast furnace efficiencies resulting from the use of high grade iron ore concentrates, has created considerable interest in the development of low grade iron deposits throughout North America. As a result, the low grade magnetite deposits of the "Grenville" region of eastern Ontario and western Quebec have received considerable attention, and several large deposits such as the Marmora and Hilton mines have recently been brought into production. With this in mind, the writer was commissioned by Hull Iron Mines, Ltd., of Montreal to investigate a group of small magnetite deposits north of Hull, Quebec, which they are presently developing.

This thesis presents the results of a reconnaissance seismic program carried out by the Geophysics Division of the Geological Survey of Canada during the months April to August, 1960, in the Queen Elizabeth Islands, N. W. T. The seismic investigations were a part of a continuing, comprehensive, Arctic research program directed by the Polar Continental Shelf Project (P.C.S.P.). The P.C.S.P. was created by a Federal Cabinet directive in 1959 and is a division of the Department of Mines and Technical Surveys. The seismic operations in the summer of 1960 were of a preliminary and reconnaissance nature designed to measure the thickness of the sedimentary section in as many localities as possible and to lay the foundations for detailed investigations in following years.

The rocks of the two map-areas include paragneisses and acidic and basic intrusives. More than three-quarters of the rocks are of igneous origin; granitic types predominate. In the Nipissis River area granitic rocks are found west and north of the Nipissis and Nipisso Rivers, whereas basic intrusives are found east and south of the two rivers. A narrow band of paragneisses and migmatites separates the two main rock groups. Granitic rocks occupy the southern third, except for the southeast corner, and most of the northern quarter of the Nipisso Lake area.

This thesis is a petrographic study of the Intermediate Siltstone, an important sedimentary member at the Sullivan mine, Kimberley, British Columbia. In the thesis a study was made of the quartz eyes which occur at the base of the Intermediate Siltstone to determine their lateral distribution, their possible origin, and whether or not they have preferred optic orientation. The Sullivan mine Is on the south slope of Sullivan Hill, 1.5 miles north-west of the town of Kimberley in southeastern British Columbia, and 50 miles north of the International Boundary.

During the field season of 1952, the writer was employed on a geological survey party of the Ontario Department of Mines. The area examined is located in the Lumby lake greenstone belt, District of Kenora, Ontario, and the work was under the direction of R. S. Woolverton (1953) who has presented a doctoral dissertation of the geology of the area. During the course of the fieldwork many problems concerning the genesis of the rocks were encountered. Woolverton has dealt with some of them in his dissertation.

Quartz suitable for glass-making and as a source of silica for other industrial uses is being mined at St. Donat, Quebec, (frontispiece) by Dominion Silica Corporation. The writer undertook a field and laboratory study of the quartz deposits and surrounding rocks, the results of which are set forth below. The following problems were studied in detail; 1.the rocks present, their composition, distribution, and structure, 2. the genesis of the quartz deposit, 3• the source of the associated kaolin.

The northern flank of the Gaspesian extension of the Appalachian Mountain System is dominated by a belt of hills 2 to 12 miles in width which begins some 15 miles east of Lake Matapedia and extends 65 miles northeastward to end with the Tabletop mountains. This high belt, known as the Shickshock mountains, forms a physiographic but not geological unit, its eastern end being composed of intrusive granite and serpentine bodies whereas, to the west, over some two-thirds of its length, the peaks are the dissected remnants of a great block of Lower Paleozoic metavolcanic and associated metasedimentary rocks.