464 LOUIS AGASSIZ. 



his arrival in the United States, but nowhere 

 had he found them in greater distinctness 

 than on the shores of Lake Superior. As 

 the evidence accumulated about him, he be- 

 came more than ever satisfied that the power 

 which had modeled and grooved the rocks 

 all over the country, and clothed it with a 

 sheet of loose material reaching to the sea, 

 must have been the same which had left hke 

 traces in Europe. In a continent of wide 

 plains and unbroken surfaces, and, therefore, 

 with few centres of glacial action, the phenom- 

 ena were more widely and uniformly scat- 

 tered than in Europe. But their special de- 

 tails, down to the closest minutiae, were the 

 same, while their definite circumscription and 

 evenness of distribution forbade the idea of 

 currents or floods as the moving cause. Here, 

 as elsewhere, Agassiz recognized at once the 

 comprehensive scope of the phenomena. The 

 whole history reconstructed itself in his mind, 

 to the time when a sheet of ice clothed the 

 land, reaching the Atlantic sea-board, as it 

 now does the coast of Spitzbergen and the 

 Arctic shores. 



He made also a careful survey of the local 

 geology of Lake Superior, and especially of 

 the system of dykes, by the action of which 



