212 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



Appalachian region, with a temperate and snbalpine flora. 

 The second embraces the Pacific slope, and is subdivisible 

 into a very humid, cool, forest-clad Coast range ; the great, 

 hot, drier California valley, formed by the San Joachin and 

 the Sacramento, flowing (the one north, the other south) into 

 the bay of San Francisco ; and the Sierra Nevada, with a 

 temperate, subalpine, and alpine flora. The vegetation of the 

 third, or Rocky Mountain region, comprising all the country 

 lying between the two districts already mentioned, is sub- 

 divisible into a prairie flora, found principally along the east- 

 ern flanks of the Rocky Mountains proper ; a desert or saline 

 flora, covering the greater part of Nevada, Utah, and Ari- 

 zona; and a Rocky Mountain proper flora, temperate, sub- 

 alpine, and alpine. The Appalachians and the Rocky Moun- 

 tains, therefore, severally divide the floras of their respective 

 districts into separate east and west sections ; while in the 

 California district, a hot and dry valley effects a similar re- 

 sult by intervening between two parallel ranges of moun- 

 tains. The difference between the Atlantic and Pacific floras 

 is specifically and to a great extent generically absolute, 

 not a pine, oak, maple, elm, plane, or birch of Eastern Amer- 

 ica extending to Western, and genera of thirty to fifty spe- 

 cies being confined to each. The Rocky Mountain region, 

 again, though abundantly distinct from both, has a few el- 

 ements of the Eastern region, and still more of the Western. 

 Under the auspices of the same survey, Professor Joseph 

 Leidy, of Philadelphia, made a careful examination of the 

 country about Fort Bridger, Wy., and of the Salt Lake ba- 

 sin, to study in life the fresh-water rhizopods of that region, 

 in preparation of a work for the survey upon the subject; 

 and Messrs. S. II. Scudder and F. C. Bowditch, of Cambridge 

 and Boston, travelled through much of Colorado and Wy- 

 oming, and a corner of Utah, making collections of recent 

 insects; but especially in search of fossil insects, which were 

 known to occur at various distant points in the Rocky Moun- 

 tain region. Travelling most of the time, they made their 

 longest halts at Green River, Wy., and at Florissant, near 

 Manitou, Col., in both of which places fossil insects are abun- 

 dant in the Tertiary beds. In the former locality, however, 

 most of them proved so imperfect and indistinct as to be 

 nearly useless for study; but at the latter they found a de- 



