LIFE OF JAMES DWIGHT DANA 



a volcanic region, in ancient time. I have cited some of 

 the facts respecting the great Tertiary outflows in my 

 Geology. It is surprising that the Duke of Argyll should 

 have found fault with your views on erosion and the 

 conclusions therefrom ; and especially that he should 

 have discovered anything of a sceptical tendency in them. 

 My range of travel through the Pacific and over parts of 

 the adjoining continents early impressed me with the 

 truth of the Huttonian view; and I still hold that erosion 

 has shaped the mountains, and mainly fresh-water erosion 

 not marine. I shall be happy to send you a copy of 

 my Geology when it is out. The work is largely rewritten 

 and much enlarged; but on the subject of valley-making 

 it is unaltered, agreeing, I believe, with the views you 

 entertain." 



DANA TO GEIKIE 



" NEW HAVEN, October 5, 1879. 



" I rejoice to know that you will give me the pleasure 

 of an excursion with you on Saturday next (the nth). 

 My walks with the students are wholly voluntary, and 

 any other day will serve them as well. I do not know 

 what may be your preference as to time of starting on 

 Saturday morning. We are early risers here being 

 made so by University duties; and I shall be ready by 

 eight o'clock or any time thereafter that is agreeable to 

 you. With horses, we could drive to several places of 

 interest, and make the most of the time. After a lunch 

 at one or two o'clock we could either go off again or visit 

 the Museum of the University, which contains much of 

 Rocky Mountain interest in Professor Marsh's collections. 

 His latest novelties are marsupial remains from the Colo- 

 rado Jurassic; but the most marvellous of his discoveries 

 is the Devonian skeleton with femur eight feet long, 

 that is, next to his toothed birds. ' ' 



DANA TO GEIKIE 



" NEW HAVEN, October 23, 1879. 



' I have put up for you a few specimens to show what 

 are Taconic rocks and those associated with them to the 

 eastward. If you arrange them geographically you will 



334 



