The Grondines map-area is about twenty miles northeast of the city of Three Rivers, Quebec. Its northern and southern boundaries are latitudes 46°45' and 46°30' respectively, and its eastern and western limits are longitudes 72°00' and 72°30'. A small part of the area is south of the St. Lawrence river, which crosses the southeastern corner of the sheet. More than half the map-area is underlain by Paleozoic rocks of which the Trenton formation is the most widespread. The area of the Trenton is a little less than that of the combined area of the Black River, Lorraine, Richmond, and Queenston formation.

Note: Missing pg 10. / Ever since the discovery of iron and gold in the Michipicoten area, a large amount of investigation has been done in an effort to explain the geology and its many interesting problems. This writer spent the summers of 1950, 1951, and 1952 in the area, while in the employ of Jalore Mining Company, Limited. During this time he examined the regional setting and the detailed geology of the iron formations and other rock formations, and wrote a Master of Science thesis on the Lucy Orebody. In the course of these investigations he became aware that much could still be added to the geologic picture, especially concerning the problems of the genesis of the iron formation, and the structure of the area.

In March, 1886, many years of prospecting culminated in a rich gold strike on the farm Langlaagte, in that part of the Transvaal now known as the Witwatersrand. This farm is now part of the city of Johannesburg (see Plate 1). The gold was discovered in a conglomerate bed, later to be known as the Main Reef. As this conglomerate was traced along its outcrop, it was quickly realised that a new and important goldfield had been discovered. That this view was justified is evident from Plate l, which shows all the areas held under mining lease today in the Transvaal and Orange Free State, totalling some 700 sq. miles.

During the period 1946-1956 geochemical prospecting methods were extensively utilized by mining companies in North America, especially in base metal exploration. At this time three types of geochemical prospecting methods were most widely used: water, stream sediment, and soil testing. These techniques were popularized through the studies of H. E. Hawkes and his colleagues. All inorganic materials of extreme fineness are sorptive. The clays additionally have crystal lattice properties which make them highly sorptive. This phenomenon bad been realized by soil scientists from their plant researches.

This thesis is concerned with the ultrabasic rocks, especially the peridotites, throughout Northwestern Quebec. Its purpose is the correlation of information on the metamorphism, associations and age relationships of these ultrabasic rocks. This will involve a general review of the variable petrology of all the ultrabaslc rocks, their regional settings and their modes of origin coupled with a detailed study of the ultrabasic rocks in those areas of which the writer has personal knowledge.

The first high temperature experiments on natural rocks were carried out by Sir James Hall, and the results published in the "Transactions of the Royal Society of Edinburgh" in 1798. In these experiments, Hall heated a number of rocks in a furnace that was used for making bricks. The temperature was measured by means or a resistance thermometer (the first of its kind) which was constructed by Wedgwood. Hall found that hornblende and other mafic minerals were the first to melt when the rocks were heated. These minerals vitrified at moderate heat but the feldspar remained unchanged.

Mount Royal is one of the three "mountains" or hills on the island of Montreal. Mount Royal, Outremont and Westmount mountains are within a circle of two miles radius and are separated by rolling ground with a relief of 100 feet. The principal exposures that were studied are: the cliff face at the north portal of the tramway tunnel in Mount Royal, and further exposures north of this along the tramway track; the cliff on the southeast side of Mount Royal in the vicinity of the lookout; and the quarry face on the northeast side of Westmount mountain. (see Map.)

This thesis is a discussion of the origin of the chert in the Ordovician limestone of the Saint Lawrence lowlands. The chert is dark grey to black in colour. It occurs as beds and variously shaped nodules, and in one outcrop, as vein-like or dyke-like tabular masses. The chert appears at three different horizons. At the base of the Beekmantown group, the top of the Black River group, and near to the base of the Trenton group.

The recent development of rich iron ore deposits in the heart of the Labrador-Ungava peninsula, with the subsequent construction of a 350 mi. railway connecting the deposits to the St. Lawrence River, has opened the door to the exploration of a vast region rich in indications of iron and base metal mineralization. Systematic exploration of this hitherto inaccessible territory has revealed that potentially economic concentrations of iron, copper and nickel lie within the “Labrador Trough”, a belt of ancient, more or less deformed sediments, which stretches at least five hundred miles from Menihek Lake in the south, northwestward to Payne Bay.

The writer takes this opportunity to acknowledge the encouragement and guidance received from Dr. V.A. Saull under whose direction these experiments were carried out. The interest shown and suggestions offered by the writer is colleagues are greatly appreciated. Financial assistance was received through Research Grant number 26-53 awarded to Dr. Saull by the Geological Survey of Canada.