trees (brush) parting to the right left of the creek 
which here turns to the northeast. There is a triangular 
shaped area of bare grassed hills and low rounded ridges 
enclosed by these two lines of timber and Yellowstone 
River. The Mud geysers at one corner, the Sulphur glen 
said the southwest and the mouth of Alum Greek at the other. 
On the steeper faces of the hill there are whitish exposures in 
which by digging with our hammers we came upon horizontally 
bedded sandy clays . There were no good exposures as the 
formation crumbles so easily. These are very probably 
the past pleocene lake beds mentioned by Hayden and Peale. 
This extent here I brieve to be pretty clearly 
indicated by the tx*eeless district. Their want of compactness 
prevent the forest from growing although a few patches of 
pines are scattered over the area (see map in sketch book). 
There are a few masses of pitchstone end trachyte scattered 
over the area and the first pebbles of metamorphic rock were 
here observed since entering the park, and they were few. 
The material is very fine. In the middle part of Alum Greek 
valley are some small outcrops of pitchstone in which are 
enclosed small masses of trachyte. Also some trachyte 
From the summits of these hills we first observed the 
brilliant white and pinkish cones of the crater hills and 
soon afterwards the Yellowstone River came in view at the 
point where it is joined by Alum Creek. To our left was Violet 
Creek and the brilliantly colored hot spring district at its 
head. Just above this In 
the timber Is the locality where 
