176 ROCHESTER ACADEMY OF SCIENCE. [May 11, 
Mr. GeorGE H. ASHLEY gave 
A REVIEW OF GILBERT'S “LAKE BONNEVILLE: 
The speaker opened by calling attention to the fascination which 
attaches to the development of such a story as that of Lake Bonneville. 
Following the definition and brief description of inland basins, 
and of our Great Basin, was given an outline history of the discovery, 
exploration and development of this region by Capt. Bonneville and 
Fremont on the Great Basin, and on Lake Bonneville, from Standsbury, 
who first noticed the shore lines, to Howell and Gilbert, the latter of 
whom named as well as described the lake. Lake Bonneville was a 
great inland sea, deeper, though smaller, than Lake Superior, and 
occupying a large part of western Utah. Existing in post-Pliocene 
times it has left to-day striking shore lines, great deltas, benches, etc. 
The story of the lake, as developed by Mr. Gilbert, is briefly as 
follows : 
The region was long a dry one. A change in atmospheric condi- 
tions, the causes for which were discussed, resulted in a slow and 
unsteady but gradual rise of accumulating, water until it was 1,000 
feet deep, and covered an area of 40,000 square miles. A long 
period of rest followed, when the previous conditions returned and the 
waters subsided. 
After a long period under the arid conditions the disturbing 
causes reappeared, and again the lake rose, with frequent pauses, 
which produced numerous shore lines. Rising 70 feet above the first 
high water mark it overflowed a great alluvial deposit in a pass to the 
north. It rapidly cut its way 475 feet through the deposit to rock 
bottom, forming a mighty river to the Columbia, and lowering the 
lake the same distance. A long stand at this point resulted in what 
Mr. Howell called the Provo shore-line, characterized by its great 
deltas and beaches. 
After standing atime, estimated at five times the wait at the 
Bonneville shore line, a return of pre-existing conditions caused the 
waters to subside, with a number of stops, the principal one being the 
Standsbury, half-way down to the present level of Great Salt Lake. 
Faulting, glacial and volcanic action, were discussed in their 
relation to the history of Lake Bonneville, and the speaker ended with 
a history of some interesting changes that have taken place in that 
region in the last quarter century. 
The paper was illustrated by a map. 
