280 HYPSOMETRIC ADDENDA. 



Mountains and the Sierra Nevada of California, has received 

 most important additions, geologically, botanically, hypso- 

 metrically, and geographically by astronomical determina- 

 tions of position, from the excellent works of Charles Fre- 

 mont (Geographical Memoir upon Upper California, an 

 illustration of his Map of Oregon and California, 1848) ; of 

 Dr. Wislizenus (Memoir of a Tour to Northern Mexico, 

 connected with Col. Doniphan's Expedition, 1848) ; and of 

 Lieutenants Abert and Peck (Expedition on the Upper Ar- 

 kansas, 1845; and Examination of New Mexico in 1846 

 and 1847.) There prevails throughout these different 

 North American works a true scientific spirit, which is de- 

 serving of the greatest commendation. The remarkable 

 elevated plain, which rises to an uninterrupted height of 

 four or five thousand Trench (4260 and 5330 English) feet, 

 between the Rocky Mountains and the Sierra Nevada of 

 California, of which I have spoken in p. 44, and which is 

 called the Great Basin, forms an inland closed river basin> 

 and has hot springs and salt lakes. None of its rivers, 

 Bear River, Carson River, and Humboldt River, find their 

 way to the sea. The Lake, which I was led by combina- 

 tions and inferences to represent, in the great Map of Mexico 

 drawn by me in 1804, under the name of Lake Timpano- 

 gos, is the great Salt Lake of Fremont's Map : it is sixty 

 geographical miles long from north to south, and ten broad ; 

 and it communicates with the fresh water lake of Utah, 

 which is situated at a higher level, and receives the Timpa- 

 nogos or Timpanaozu River, which enters it from the east- 

 ward, in lat. 40 13'. The circumstance of the Timpano- 



