758 THE JOURNAL OF GEOLOGY. 



In 1872 Agassiz went through the Straits of Magellan in 

 charge of the natural history work of the Hassler Expedition. 

 On that voyage he touched at Montevideo and at many points 

 south of that place, through the straits, and along the west coast. 

 The letters written by him on this trip suggest very strongly, if 

 they do not conclusively show, that he had at this time already 

 abandoned the idea that Brazil had been glaciated. Speaking of 

 certain boulders seen by him on the Cerro at Montevideo, Mrs. 

 Agassiz observes 1 that "As these were the most northern erratics 

 and glaciated surfaces reported in the southern hemisphere," etc. 

 From this it appears that he no longer regarded the Brazilian 

 boulders as erratics. 



After Agassiz had examined the glacial phenomena of the 

 Straits of Magellan and of the southern part of the continent, he 

 sent a report to the Superintendent of the U. S. Coast Survey, 

 dated at Concepcion Bay, June I, 1872. 2 This article also bears 

 evidence that he no longer regarded Brazil as having been glaciated. 

 In one place he says, 3 " I am prepared to maintain that the whole 

 southern extremity of the American continent has been uniformly 

 moulded by a continuous sheet of ice." The italics are mine. In 

 the next paragraph he says, "The first unquestionable roches 

 moutonnees I saw were upon the nearest coast opposite Cape 

 Froward." Again he says (p. 271): "The equatorial limit of 

 this ice sheet both in the northern and the southern hemisphere 

 is part of the problem upon which we have thus far fewest facts 

 in our possession. In South America I have now traced the 

 facts from the southernmost poiiit of 'the continent uninterruptedly to jy° 

 S. latitude on the Atlantic as well as the Pacific coast." Again 



1 Louis Agassiz, his Life and Correspondence, Boston, 1886, II., 712. Rep. U. S. 

 Coast and Geodetic Survey for 1872, 215. Nature, 1872, VI., 69. Evidently Burmeister 

 does.not regard the boulders cited as glacial, for he uses the expression, "phenomenes 

 de glaciers chez nous, et dont nous n'avons nulle part la preuve." Republique Argen- 

 tine, II., 214, also 392, 393. The same blocks are described by Darwin in his Geolog- 

 ical Observations, 432. He does not seem to regard them as erratics. 



2 Published in the New York Tribune of June 26, 1872, and reproduced in Nature 

 1872, VI., 216, 229 and 260. 



3 Nature, 1872, VI., 230. 



