116 NATHANIEL SOUTHGATE SEALER 



needed in my work. Marcou's main influence on me while I 

 was a student came through his great knowledge of men and 

 their deeds. He knew the work of the leaders of the science 

 very well, and his intense interest in people, and delight in 

 talking about them, helped me to get the traditions of the sci- 

 ence. To him and afterwards to Lyell I owe a considerable 

 amount of knowledge of what geologists have done and their 

 quality not only as men of science but as men. I have never 

 found any one else so rich in this important lore. 



In 1860 I came in contact with the brothers Rogers, William 

 and Henry, then famous for their work in Virginia and Penn- 

 sylvania. With the latter of these able men my personal con- 

 tacts were limited, but I heard him expound his theory of 

 mountain-building, which was in effect that mountains were 

 great translation waves in the crust, made by earthquakes, 

 essentially like those made by the wind on the surface of the 

 sea, which had been arrested in their forward movement and 

 remained as it were frozen as we now find them, except for the 

 changes which erosion has brought about. I am glad to say 

 that in the debates on this hypothesis in our club, I set myself 

 against it, on the ground that we see no such waves attending 

 earthquakes, and further that the rocks would be shattered by 

 such movements and not folded as we find them. It was by such 

 debates on every question which came up that I had much of 

 the best training of my undergraduate time. Probably it was 

 this proposition of Henry D. Rogers that fixed my interest on 

 mountain structures and led me to read nearly all that had 

 been written on the subject. 



With William B. Rogers, as he had married in Boston and 

 come to live there, my relations were nearer than with his bro- 

 ther Henry. We met in the Society of Natural History, where, 

 as above noted, I was wont to contrive debates between him 

 and Agassiz. I can see before me now the noble shape and 

 brilliant countenance of my master, as he eagerly, often in- 

 cautiously, set forth his hypothesis, while Rogers, keen-faced 



