Page:The Journal of geology (IA journalofgeology11893univers).pdf/336

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 1, 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 paragraphs he says, "The first unquestionable roches moutonnées 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 point of the continent uninterruptedly to 37° S. latitude on the Atlantic as well as the Pacific coast." Again