OSCILLATION INDEPENDENT OF GLAGIATION. 513 



more in Jamaica and Cuba/ and of about 1,100 feet in Barbados;- the 

 recent uplift of the coast of Peru at least 2,900 feet,^ which in diminished 

 amount seems to extend along tlie whole range of the Andes;* its probable 

 connection with the upheaval of the Cordilleras of North America, where 

 Le Conte^ and Diller" believe that the elevatory movements reached their 

 greatest intensity in early Quaternary time, causing a rise of several 

 thousands of feet in the Sierra Nevada; and the apparently coi-relative 

 subsidence of a great area dotted with coral islands in the Pacific. The 

 Pleistocene uplifts of the Andes and Rocky Mountains and of the West 

 Indies make it nearly certain that the Isthmus of Panama has been simi- 

 larly elevated during this period. On the line of the Panama Railway the 

 highest land rises only 299 feet above the sea, and the highest on the pro- 

 posed route of the Nicaragua Canal is about 133 feet; while the Isthmus 

 nowhere attains the height of 1,000 feet.' It may be true, therefore, 

 that submergence of this isthmus was one of the causes of the Glacial 

 period, the continuance of tlie equatorial oceanic current westward into the 

 Pacific having greatly diminished the Gulf Stream, which carries warmth 

 from the tropics to the northern Atlantic and northwestern Europe. 



Pleistocene mountain-building is known to have occurred on a most 

 massive scale in Asia, where the Himalayas, stretching 1,500 miles from 

 east to west, and towering 20,000 to 29,000 feet above the sea, are known 

 to have been formed in great part during this latest geologic period,^ con- 



' J. 6. SawkiDS, Reports oii the Geology of Jamaica, 1869, pp. 22, 23, 307, 311, 324-329 ; W. O. Crosby, 

 "On the monutains of eastern Cuba,'' Appalachia, Vol. Ill, pp. 129-142. Compare William M. Gabb's 

 memoir, "On the topography and geology of Santo Domingo," Trans., Am. Phil. Soc, Vol. XV, pp. 

 103-111. 



^ "The geology of Barbados," by A. J. Jukes-Browne and J. B. Harrison, Quart. Jour. Geol. Soc, 

 Vol. XLVII, pp. 197-250, Feb., 1891. 



' A. Agassiz, Proc, Am. Acad, of Arts and Sciences, Vol. XI, 1876, p. 287 ; and Bulletin of the Museum 

 of Comparative Zoology at Harvard College, Vol. Ill, pp. 287-290. Above this height, at which corals 

 are found attached to rocks, recent elevation of much greater amount seems to be indicated by 

 terraces, by saline deposits, and by the presence of eight species of AUorchestes, a marine genus of 

 Crustacea, in Lake Titicaca, 12,500 feet above the sea. 



■* Darwin's Voyage of the Beagle, Chapter XVI. 



s Am. Jour. Sci. (3), Vol. XXXII, pp. 167-181, Sept ., 1886 ; Vol. XXXVIII, pp. 257-263, Oct., 1889. 



« U. S. Geol. Survey, Eighth Annual Report, for 1886-87, pp, 428-432. 



' Charles Ricketts, "The cause of the Glacial period, with reference to the British Isles," Geol. 

 Magazine (2), Vol. II, 1875, pp. 573-580. A. R. Wallace, The Geographical Distribution of Animals, Vol. 

 I, p. 40. 



"Manual of the Geology of India, by H. B. Medlicott and W. T. Blanford; Calcutta, 1879; Part 

 I, pp. Ivi, 372; Part II, pp. 569-571, 667-669, 672-681. 

 HON XXV 33 



