206 YIEWS OF NATURE. 



prevails throughout these North Americau works a scientific 

 spirit deserving of the warmest acknowledgment. The re- 

 markable plateau, referred to in p. 34, between the Rocky 

 Mountains and the Sierra Nevada of California, which rises 

 uninterruptedly from 4000 to 5000 French (4260 to 5330 

 English) feet high, and is termed the Great Basin, presents 

 an interior closed river- system, thermal springs, and salt 

 lakes. None of its rivers, Bear River, Carson River, and 

 Humboldt River, find a passage to the sea. That which, 

 by a process of induction and combination, I represented 

 in my great map of Mexico, executed in 1804, as the Lake 

 of Timpanogos, is the Great Salt Lake of Fremont's map. 

 It is 60 miles long from north to south, and 40 miles 

 broad, and it communicates with the fresh- water Lake of 

 Utah, which lies at a higher level, and into which the 

 Timpanogos or Timpanaozu River enters from the eastward, 

 in lat. 40° 1 3 . The fact of the Lake of Timpanogos not 

 having been placed in my map sufficiently to the north and 

 west, arose from the entire absence, at that period, of all 

 astronomical determinations of position of Santa Fe in New 

 Mexico. For the western margin of the lake the error 

 amounts to almost fifty minutes, a difference of absolute lon- 

 gitude which will appear less striking when it is remembered 

 that my itinerary map of Guanaxuato could only be based 

 for an extent of 15° of latitude on determinations made by 

 the compass (magnetic surveys), instituted by Don Pedro de 

 Rivera. § These determinations gave my talented and prema- 

 turely lost fellow-labourer, Herr Friesen, 105° 36' as the lon- 

 gitude of Santa Fe, while, by other combinations, I calculated 

 it at 1 04° 51'. According to actual astronomical determinations 

 the true longitude appears to be 106°. The relative position 

 of the strata of rock salt found in thick strata of red clay, 

 south-east of the Great Salt Lake (Laguna de Timpanogos), 

 with its many islands, and near the present Fort Mormon 

 and the Utah Lake, is accurately given in my large map of 

 Mexico. I may refer to the most recent evidence of the tra- 

 veller who made the first trustworthy determinations of posi- 

 tion in this region. " The mineral or rock salt, of which a 

 specimen is placed in Congress Library, was found in the 

 place marked by Humboldt in his map of New Spain (north- 



* Humboldt, Essai %>olit. sur la Nouvclle Esxxigne, t. i. pp. 127-136. 



