64 MEMOIRS OF THE CARNEGIE MUSEUM 
colored, massive sandstones generally referred to as Dakota, although neither here 
nor elsewhere in this region in so far as I am aware, are these sandstones clearly 
distinguishable from the Jurassic. Cottage Rock is situated about three quarters of 
a mile north of the Marsh quarry and the top of the uppermost shales in this butte 
which are clearly recognizable as pertaining to the Atlantosaurus beds is estimated 
to be from 300 to 350 feet above the bone-bearing horizon at the Marsh quarry. 
The isolated conical butte shown in Fig. 26, and locally known as the ‘“ Nipple’ 
is situated some 300 yards back and a little to the right of “ Cottage Rock.” It 
? 
Fie. 26. The ‘‘ Nipple’’ from the north, showing in the foreground the trench cut by Professor Cope 
in collecting Dinosaur remains. 
stands on the edge of the escarpment overlooking the valley of “Garden Park” 
through which flows Oil Creek. This epee butte is composed almost entirely of 
shales pertaining to the uppermost Atlantosawrus beds. It is capped with a mere 
remnant of a former sandstone ledge belonging either to the top of the Atlantosawrus 
beds or the base of the Dakota. About the base and over the slopes of this butte 
fragmentary dinosaurian remains occur in considerable abundance and the locality 
was worked to a considerable extent by Professor Cope. One of his abandoned 
trenches may be seen on the left at the foot of the butte in the photograph. 
