PISHES. 51. 



the shallows of lakes in the fall and conceal them- 

 selves in the grass. They^have red spots on the 

 bod}^, and square tails. The other kind have 

 yellow spots and forked tails, and never leave the 

 lakes. I am told that Oneida Lake is filled in 

 July with a small substance called lake blossom, 

 which is undoubtedly the exuviae or ova of in- 

 sects. I have seen on the Lake Baikal, the great- 

 est lake of the old world, vast quantities of the 

 skins of the onischus trachurus, a species of insect 

 which abounds on the rocky shores of the lake, 

 and is the food of the salmo lenok and sig. The 

 salmo salar and its congeners is probably attracted 

 into these lakes by the vast quantities of insects. 

 I have heard a great deal of the Oswego basse^ 

 or black basse ; it is said to be the most delicious 

 fish of the west. It is of the perca genus. 



LETTER XL 



Canandaigua, June, 1820. 

 My Dear Sir, 



Lake Baikal, of which I wrote to you in a late 

 letter, is a vast distance from the sea. It is 125 

 leagues long, and about six in breadth. A species 

 of seal inhabits it, which was originally a sea 

 animal, but which is now naturalized to fresh 



