14 LAKE SUPERIOR. 



" Among the plants peculiar to this country, are many in whose ana- 

 logues in Europe many interesting chemical products have been traced. 

 Very little has been done here in organic chemistry, and it is a matter which 

 might well occupy one's lifetime, to ascertain the chemical relations of 

 analogous plants of the two countries, (for instance, Angelica, wal- 

 nut, &c.) Tracing the forest vegetation, we have seen lately very few 

 pines, but principally maples, elms, and ashes ; and here at Niagara, almost 

 exclusively elm, beech, hickory, ash, and arbor-vitae, which is very rare in 

 Massachusetts." 



June \'^tli. — We met a2:ain this mornino; in the hall, where Prof. 

 Agasslz had prepared diagrams illustrating the geology of Niagara, 

 which he explained as follows : — 



" The surface of the soil, both on the Canadian and on the American side, is 

 covered with gravel, containing fossils in great numbers, and stones of all sizes, 

 from that of a hen's egg to large bowlders. This stratum is now disunited by 

 the action of the river, but was originally continuous, as is shown by the 

 fossils, and by the fact that on the intermediate islands, where it has escaped 

 the action of the water, it is still present. The fossils form a bed extending 

 horizontally to the river bluffs, but not beyond ; they occur in great num- 

 bers, covering the surface of the soil everywhere, and contributing to the 

 great luxuriance of the vegetation. These fossil shells, doubtless, inhabited 

 the river in former times, when its bed was the mass of gravel, &c., on which 

 they now rest, the bluffs being at that time its banks. They are of species 

 now living in the river, of the genera Unio, Cyclas, Melania, Paludina, and 

 Planorhis. Hence we conclude that this bed was formed when the river 

 filled the whole valley, at which time it had a breadth varying from one to 

 seven miles, and averaging three or four. Probably at that time it resem- 

 bled the present Rapids above Goat Island. Afterwards, from the accelera- 

 tion of the current, owing probably to the opening of fissures which lowered 

 the level of Lake Erie, the two present channels were cut down to the rock, 

 and the river reduced to its present level." 



Afterwards we went over to Goat Island, and blessed once more 

 the good sense that has kept this place undisturbed. The decaying 

 wood and fungi of the damp woods here afforded an abundance of 

 specimens to our entomologists. The variety of trees and shrubs on 

 these islands is remarkable. On the little islet (only a few feet 

 m extent,) connected by a foot-bridge with the toll-house, Prof. 



