90 PROCEEDINGS OF THE CALIFORNIA 



the lake was once 600 feet higlier than now. He added that Pyra- 

 mid and Great Salt Lake^ had also risen very much in the past two 

 years. He thought there were probably cycles of rise and fall in 

 the waters of the Great Basm corresponding to periodical changes 

 of the climate. There had been an unusually large rainfall east^of 

 the Sierra Nevada in the past year. 



A discussion followed on the probability of these facts being con- 

 nected with the uncommonly small rainfall in California this winter. 



Regular Meeting, December 20th, 1869. 

 President in the Chair. 



Fifteen members present. 



Donation to the Cabinet: A fresh specimen of Casinos hipinnata 

 raised from seed sent from Guadalajara, Mex., by Baron Terloot, 

 by Dr. Behr. 



Prof. Whitney read the following paper : 



Notice of Explorations in the Rocky Mountains. 



BY J. D. WHITNEY. 



Professor Whitney gave some of tlie results obtained in an exploration of a 

 portion of the Rocky Mountains durinjf the previous summer. Tlie party, 

 which was well provided with instruments for topographical, astronomical, and 

 barometrical work, consisted chiefly of professors and students from the Mining 

 School of Harvard University, and was also accompanied by Professor Brewer, 

 of the Yale Scientific School, and Mr. C. F. Hoffmann, of San Francisco. A 

 careful triangulation was made of the dominating range of the Rocky Moun- 

 tains between Gray's Peak and the south edge of the South Park, and a map 

 drawn by Mr. Hoffmann, on a scale of two miles to an inch, embracing an area 

 of about 3,.o00 square miles. This map includes the whole of the South Park 

 and its vicinity ; but not the whole of the main divide of the Rocky Mountains, 

 that portion which lies to the northwest of the head of the Arkansas River 

 being necessarily left to be completed at a future time. It is hoped that it will 

 be possible to extend the topographical work to the north and west, so that a 

 detailed map may be prepared of the whole of the highest portion of the Rocky 

 Mountains. 



Among the results obtained by this exploration was the determination of the 

 elevation of some high points not previously measured. The highest peak as- 

 cended lies to the west of the Arkansas, and it surpasses in elevation any yet 



