The present study is a report on the volcanic deposits which form the southern part of the Absaroka Range and which occur in the adjoining region in northwestern T/yoraing* This investigation has been undertaken with the object of eliminating discrepancies in correlation within the lower subdivisions of the Absaroka Range, chiefly between the Bighorn and Wind River basins.

Stream sediment geochemistry has been described as a very robust, successful mineral exploration technique and has proven to be effective even when sampling was poorly carried out (Fletcher, 1997). Much of its early success for discovering new mineral deposits in British Columbia can be traced to the pioneers of exploration geochemistry who recognized the ability of more mobile elements such as copper and zinc to concentrate in sediment from broad range of stream environments. This proved to be an advantage in the 1950’s when exploration focused primarily on the search for porphyry copper deposits. Sediment sampling techniques could afford to be less rigorous because formation of copper stream geochemical anomalies was less susceptible to the variations in sample site environment. However, it became apparent that geochemical surveys for gold and other heavy minerals needed more careful collection of sediment from a specific energy environment so that maximum anomaly contrast could be achieved. <...>

Structural geology records colossal work done by natural forces on the visible and invisible rocks of every continent. The energy expended in this work has been chiefly of two kinds—solar and terrestrial. Geologists of the nineteenth century paid particular attention to the part played by solar radiation in governing the dynamical history of the outer earth. A leading project of the twentieth century is to learn how the conditions of the planet's deep interior have also controlled the same history.