A TRIP THROUGH NORTHWESTERN WYOMING. 
By A. D. WILSON.* 
Air. Wilson commenced by giving an outline of the geological 
formation and general features of the Wind River mountains, 
which lie at the northwest corner of Wyoming, extending to the 
borders of Idaho, and running south of the Yellowstone Park. 
Mr. Wilson, in the year 187S, was in charge of a small party 
belonging to the United States Geological Survey, who were then 
making a topographical examination of this little known part of 
the country. His party followed a route from Point of Rocks sta¬ 
tion on the Union Pacific, northward through the Wind River 
mountains, afterwards striking the Teton mountains, thence 
through a singularly wild defile into the Yellowstone Park. The 
Wind River mountains consist geologically of later formations at 
the base, but of granite and Gneiss through the main range and 
along all the summits. Glaciers still exist throughout this region, 
and their past action is plainly seen in the peculiarly scooped 
granite basins, now occupied by lakes, and also in the great quan¬ 
tity of morainal matter carried out into the valleys where it is now 
accumulated in picturesque shapes, piled in some cases to the 
height of 1000 feet above the valleys. Deeply cut canons exist 
at all points of the range, with almost perpendicular walls running 
up to fully 2000 feet. The mountains themselves are very jagged 
and bare of vegetation, but the slopes at the foot are covered with 
pine timber. Deer and elk abound along the valleys, which are 
traversed by streams full of trout, while in the hill ranges grizzly 
bears are plentiful. 
Air. Wilson ascended Fremont’s Peak and other notable 
points, and gave a vivid description of the dangers and almost 
unsurmountable difficulties attending such mountain climbing. 
Though it was July when the little exploring party made 
their journey, they found the mountain lakes they had to 
cross, so thickly frozen that they were able to cross from point to 
point on foot. Following the march, they next came to the 
♦Abstract of lecture delivered before the Society, on February Sth, 1SS4. 
