92 Correspondence — Mr. Warren TTpham. 



of these funnel -holes must have been the chemical and solvent action 

 of the water from its own snowdrift, aided to some extent by the 

 mechanical work of the frost. Alfred Ely Day. 



Syrian Protestant College, Beirut. 



ELEVATION AND SUBSIDENCE DURING THE GLACIAL PERIOD. 

 Sir, — In reply to the article by A. J. Jukes Browne (Geological 

 Magazine, December, 1890, p. 561), concerning high continental 

 elevation of America with relation to the Glacial period, I may 

 refer to my appendix in Prof. G. F. Wright's " Ice Age in North 

 America," as containing a review of evidences of subsidence in the 

 West Indies, cited in that article, probably contemporaneous with 

 the elevation and glaciation of the northern part of North America. 

 It was pointed out fifteen years ago by Dr. Eicketts (Geol. Mag. 

 Dec. II. Vol. II. 1875, pp. 573-580) that submergence of the 

 Isthmus of Panama may have been an important element in the 

 causes of the Glacial period ; and at about the same time the collection 

 by Dr. G. A. Maack of abundant Pleistocene fossils, " all living up 

 to the present time," in the vicinity of the Panama railroad, and at 

 many localities southward to the Atrato river, ranging in height 

 up to at least 763 feet, while the lowest points of the interoceanic 

 water-shed are less than 300 feet above the sea, gave proof that 

 parts of this isthmus have been thus lately submerged (Eeports of 

 Explorations for a Ship Canal, Isthmus of Darien, United States 

 Navy Department, Washington, 1874, pp. 155-176). 



Nothing is more surely determined than the record of the Glacial 

 period, as shown by glacial drift and striae upon North America 

 from the Atlantic to the Pacific, and from southern Illinois to the 

 Arctic Sea, and upon north-western Europe from the British Isles 

 to Germany and Central Eussia, and northward across the Scandi- 

 navian peninsula. Some causes must have existed to produce the 

 great climatic changes of this period. These causes seem to me to 

 have been probably the great uplifts of the glaciated areas of which 

 Professor Spencer has cited so much evidence, and the contem- 

 poraneous depression of the region of the West Indies and Isthmus 

 of Panama, by which a part of the equatorial oceanic current that 

 sweeps northward in the Gulf Stream would be permitted to pass 

 into the Pacific Ocean, withdrawing a large portion of its heat 

 from the North Atlantic area. Correlative northern elevation and 

 southern subsidence, for both of which we have sufficient proof, 

 •would contribute almost equally to the climatic changes of the Ice 

 age. This subject, and the probably contemporaneous uplift of a 

 belt of land across the North Atlantic from France and Great Britain 

 to the Fasroe Islands, Iceland, and Greenland, as argued by Prof. 

 James Geikie in his " Prehistoric Europe," I have discussed some- 

 what fully in the American Geologist for December, 1890, and the 

 American Journal of Science for January, 1891, in the endeavour to 

 ascertain the probable causes of the remarkable Quaternary changes 

 of climate. Warren Upham. 



SoMERViLLE, Mass., January 6th, 1891. 



