X 



compressum 



X 



adamsi affine 





mainense 





ventricosum 



X 



costatum 





mediamim minutum 



X 



' conlortum 



156 LIFE OF THE PLEISTOCENE 



Shells from Lovely Brook bog, near Fort Fairfield. 



x Pisidium conlortum Physa heterostropha 



ventricosum x Planorbis crista cristata 



" splendidulum x " hirsutus 



x " abditum x " parvus 



" variabile Galba obrussa ( = desidiosa) 



Shells from Little Mud Lake, Westmoreland. 126 



Anodonia fragilis x Pisidium triangulare 



x Sphaerium simile ( = sulcatum) x " tenuissimum 



x rhomboideum " splendidulum 



x Musadium secure? " splendididum, var. * 



Pisidium variabile x " abditum? 



x Valvata sincera, var. 

 x Ancylus parallelus 

 x Planorbis campanulatus 

 x " antrosus (=bicarinatus) 



" panics 

 x " hirsutus 



x Galba obrussa 



Mr. Nylander remarks that living mollusks are very rare in this lake, but 

 that the fossil shells are very abundant. The water is evidently impregnated 

 with mineral salts and the environment is becoming unfavorable for molluscan 

 life. 



XI. CANADA 



Records of postglacial life have been definitely recorded from the territory 

 north of the Great Lakes, notably in Ontario. The biota contained in these 

 deposits is mainly lacustrine, altho a few land forms are represented, especially 

 among the plants. Toward the east there is an admixture of both fluviatile 

 and marine species, showing the close association of the lakes, rivers, and the 

 sea during the Champlain substage. Only the lacustrine and fluviatile life 

 will be exhaustively considered. 



1. Lake Algonquin Stage 

 "No animal life has been found in the beach itself. But in a terrace adja- 

 cent to the Saugeen River (bridge east of Southampton), where there is an 

 embayment of the Algonquin beach, there is a bed of fresh-water shells, dis- 

 covered by Mr. Spillman. This is at an altitude of 90 feet above the lake, or 40 

 feet below the beach. This deposit may have been on the floor of the lake dur- 

 ing the Algonquin episode, or it may belong to a lower water level. At the head 

 of Georgian Bay, fresh water shells have been found up to 78 feet." 126 No fist 

 of the species from these deposits has been observed. 



m Nautilus, XXII, pp. 105-106. The deposit is said to be many feet in thickness. 

 1M Spencer, Amer. Journ. Sci., (iii), XLI, p. 16, 1891. 



