252 ANNUAL OF SCIENTIFIC DISCOVERY. 



circumpolar belt of ten to fourteen degrees. There is no abrupt break 

 or chain in the vegetation anywhere along this belt except in the 

 meridian of Baffin's Bay, where the opposite shores present a sudden 

 change from an almost purely European flora on the east coast to one 

 with a large admixture of American plants on the west. The number 

 of flowering plants is estimated at 762 ; of cryptogamia at 925 ; total, 

 1687. Regarded as a whole, Dr. Hooker considers the Arctic flora to be 

 decidedly Scandinavian ; for Lapland, though a very small tract, con- 

 tains by far the richest Arctic flora, amounting to three-fourths of the 

 whole. Of the five districts into which Dr. Hooker divides the Arctic 

 belt, Greenland is the most remarkable ; since, although so favorably 

 situated for harboring an Arcto- American vegetation, it presents but lit- 

 tle trace thereof, and has an almost absolute identity with that of Europe. 

 This, he considers, cannot be accounted for except by admitting Mr. 

 Darwin's hypothesis of the great geological antiquity of the Scandina- 

 vian flora ; its subsequent migration southward in every latitude dur- 

 ing the glacial period, and even across the tropics into the south tem- 

 perate zone ; and the ascent of the mountains of the warmer zone by 

 many species at the commencement of the warmth of the present 

 epoch. 



HIGHEST MOUNTAINS IN THE UNITED STATES. 



Professor J. D. Whitney, the Superintendent of the California 

 Geological Survey, in an article in the Proceedings of the California 

 Academy" announces his conclusion, that Mount Shasta, 14,400 feet 

 high, probably overtops all other peaks within the limits of the United 

 States. Mount Hood, sometimes called the loftiest peak of the Cas- 

 cade Range, is probably not so high as Mounts Shast.a, Rainier or Ad- 

 ams, and by no means entitled to the supremacy of the chain, although 

 one of the highest points in it. Trigonometrical measurements of 

 Mount Hood, in 1860, give its height as 11,934 feet. 



Mount St. Elias, in the Russian Possessions, has generally been con- 

 sidered the highest mountain in North America, on the authority of 

 Malespina's manuscripts, discovered by Humboldt in the archives of 

 Mexico, which assign to it an elevation of 1 7,854 feet. Mr. Whitney, 

 however, thinks this estimate erroneous, and the estimate given on the 

 British Hydrographical charts of Captain Denham, of 14,970, more 

 nearly correct. Mount Brown and Mount Hooker, in British Columbia, 

 have assigned to them a height of 16,000 and 16,750 feet respec- 

 tively. But the highest mountain on the North American conti- 

 nent is, beyond all doubt, the Mexican volcano of Popocatapetl^ which 

 rises to the well-ascertained height of 17,783 feet. 



