492 FAUNA CANADENSIS. 



pebbles, and all the finei- materials having been washed out before it. 

 reached the surface. In about fifteen fathoms the bottom was found 

 to consist of a tenacious blue clay, distinctly laminated, and containing 

 numerous broken-up stems of plants, along Avith small pebbles. No 

 traces of life could be detected beyond a few minute Annelides of 

 the genus Scenuris. Another haul in ten fathoms brought up the 

 dredge full of sand and pebbles with no traces of life ; and another in 

 eight fathoms showed a bottom of clean sand, with dead shells of 

 Gyclas and Pisidium, but devoid of all vestiges of animal or vegetable 

 life. 



Another series of dredgings was taken along a line extending in a 

 south-east direction from Gibraltar Point to a point about five miles 

 out in the lake, the depths varying from eight to fifteen fathoms. In 

 this case the bottom was found to consist uniformly of an excessively 

 fine, bluish, argillaceous mud, with numerous patches of a small bushy 

 Alga (a species of Cladophora). The m:ud contained very numerous 

 minute AnneKdes of the genus Scenuris, along with dead shells of 

 Cyclas, Pisidium and Planorhis ; and the bunches of Cladophora 

 yielded a large number of little Ostracode Crustaceans and a few 

 beautiful little Amphipods, both of which are at present undeter- 

 mined. 



Another series of dredgings was cai-ried out still further to the 

 southwest of the ground examined in the series just mentioned, at a 

 distance of about eight miles from the shore. The deptli here varied 

 from thirty to forty or fifty fathoms ; and the bottom was found to 

 consist everywhere of a fine grayish mud, sometimes highly argillaceous, 

 ■sometimes more or less arenaceous, with many small pebbles dissemi- 

 nated tlirough it, and containing a few dead sheila of Planorhis and 

 Pisidium, with much broken down vegetable debris. The Cladophora 

 was absent, and no traces of vegetable life were detected. Every haul 

 of the dredge brought up numerous specimens of a beautiful flesh- 

 coloured Amj)hipod and a few minute Oligochsetous Amielides ; but 

 no other traces of life were obtained. The Amphipods were referable 

 to Pontoporeia, and are apparently undistinguishable from Pontoporeia 

 affinis of the great lakes of Sweden. 



Another series of dredgings was taken in Humber Bay, about four 

 miles to the west of Toronto. Here the bottom, except close to the 

 shore, consisted of a tenacious bluish-gray clayey mud, sometimea 

 with reddish patches in it. Vegetable life was very scanty j and 



