THE REIGN OF ICE. 221 



Indiana; while pebbles of quartz, gneiss, granite, dolerite, 

 and other rocks from the same regions constitute a large 

 proportion of the soil of these states. The streets of Cin- 

 cinnati are- paved with stones which were quarried by the 

 hand of Nature in the region of the upper lakes. 



Professor Agassiz, to whom we are indebted for the full 

 exposition and application of the glacial theory, thinks he 

 discovers abundant evidences of the former action of gla- 

 ciers in Brazil ; but the presence of rocky debris, and even 

 of rounded pebbles that can not be attributed to shore ac- 

 tion, is not enough to establish glacial agency, especially 

 while in the United States we do not recognize it south of 

 the Ohio River. On the contrary, Professor Whitney has 

 recently asserted that the proofs of glacial action are en- 

 tirely wanting in California, and for some distance north- 

 ward. The copious accumulations of unsolidified surface 

 materials are attributed to the slow disintegration of the 

 rocks under atmospheric agencies. 



Glaciers of almost continental extent still exist on the 

 shores of Greenland, and cover the Antarctic land dis- 

 covered by the United States Exploring Expedition ; also 

 Wrangell Land, very recently discovered by Captain Long 

 in the Arctic Ocean. Perennial ice binds the soil of North- 

 ern Siberia, and, as is well known, preserved for many cen- 

 turies the carcasses of hairy elephants incased in it. There 

 is little difficulty in believing that these high-latitude ice- 

 fields are merely the remnants of glaciers which once ex- 

 tended many degrees farther toward the south. 



