FAUNA CANADENSIS. 491 



at various depths and the chief localities in which the dredgings Avere 

 prosecuted. 



In Toronto Bay itself numerous hauls were made, both from the 

 yacht and the steamer, and the bottom proved very varied, though 

 the depth is almost constantly from two to three fathoms. The 

 greater portion of the Bay, comprising the central portion of its area, 

 appears to consist uniformly of a tenacious, bluish-gray, exceedingly 

 j&ne, clayey mud, the temperatiire of which is very low. All the 

 shells in this clay are dead, but it contains numerous small Annelides 

 of the geniis Scemtris, along with many larvaj of a Dipterous insect 

 allied to Chironomus or Corethra, the latter being very conspicuous 

 from their brilliant red colour. The muddy bottom appears to be 

 wholly destitute of weeds, and does not seem to encroach upon depths 

 of less than two fathoms. 



Towards the edges of the Bay, where the depth diminishes to one 

 and a half fathom or less, the bottom consists of sand, covered over 

 considerable areas with a dense growth of weeds of different kinds. 

 The chief varieties of bottom in this shallow zone are the following : — - 

 1. Pure siliceous sand with dead shells, almost destitute of life. 2. 

 Sandy mud with a dense growth of Charas, containing numerous 

 Gammari, small leeches, larvae of Chironomus and Ephemerids, with 

 shells of Unio, Gyclas, Fisidium, Pcdudina, Planorhis,Physa,Melania, 

 and Valvata. 3. Sandy mud, sometimes with peaty layers, supporting 

 a luxuriant vegetation of Anacharis Canadensis and Cliaroi. The 

 life in these portions of the Bay consisted of much the same animals 

 as the preceding, except that the Gammari were absent, imless in the 

 occasional [jatches of Charas brought up by the dredge. In some 

 places, in from one to one arid a half fathom of water, the sand was 

 crowded with Uniones, the dredge coming up completely packed with 

 living and dead shells. This was expecially the case at several points 

 under the lee of the ''Island," a long, flat, insulated strip of land, 

 which forms the southern boundary of the Bay, running parallel with 

 the shore on which Toronto is built, at a distance of about a mile and 

 three quarters from it. 



Another series of dredgings was garried out from a point in the open 

 lake about eight miles to the south of Toronto, on a line extending to 

 the Toronto Rolling-mills, the depth varying from forty fathoms at 

 its northern extremity. The deep dredgings along this line were only 

 partially successful, the di-edge bringing up nothing but good-sized 



