Page:The Journal of geology (IA journalofgeology21894univers).pdf/270

The Minnekahta Creek, or this southern fork of it, after flowing north through the Cretaceous, enters the Red Beds a little south of the Minnekahta Station, after which it bends to the eastward and follows the strike to Hot Springs. Below this point it takes a southeasterly course, and soon reënters the Cretaceous, cutting entirely through the sandstone and entering the dark Fort Benton Clays a short distance below the cataract at the electric light plant nearly five miles from Hot Springs at Evans Siding. Evans Quarry is just above this point on the left bank. At the last named place Professor Jenney had formerly obtained dicotyledonous leaves, and it was his impression that these might have come from near the horizon of the cycad bed. This region presents an admirable opportunity for measuring a section of the Cretaceous, which it was very desirable to do for comparison with the one last given.

The distance at the bottom of the valley from the Jurassic contact to the Fort Benton is about three miles, and the dip, as the section shows, is over 100 feet to the mile. The quarry is about one-half mile from the point where the sandstones pass under the Fort Benton shales. It has a thickness in workable stone of about 60 feet, and is immediately capped by 40 or 50 feet of softer material. It dips very rapidly to the southeast so as to come down to the stream at the electric light plant, and constitute the rock over which the cataract flows and through which the water has here worn deep longitudinal grooves. Immediately over these rocks and resting upon them there is a bed some six or eight feet in thickness of dark clay and argillaceous shales with carbonaceous matter and some impure coal. In this bed was found a great abundance of more or less comminuted vegetable matter, with short fragments of culms or reed-like plants not determinable. There also occurred in certain of the shales a few tolerably well preserved dicotyledonous leaves, some of which are determinable. They were at least sufficient to indicate with practical certainty that this stratum belongs to the Dakota Group of Meek and Hayden (No. 1). A small collection was made at this point, viz., at the cataract