148 LIFE OF THE PLEISTOCENE 



1. Algonquin Stage {Lake Iroquois) 



The post-Pliocene shells of Goat Island, Niagara River, have been known 

 for many years, but their relation to the ancient glacial lakes has but recently 

 been recognized. 88 The deposits in which the shells are found were laid down 

 during the Algonquin stage, about the time that Lake Iroquois was at its high- 

 est level. The Niagara River then connected a diminished Lake Erie with 

 Lake Iroquois. The deposits consist for the most part of coarse, subangular 

 fragments of rock, gravel, and some sand. Its depositional character shows 

 that it was laid down in rapidly flowing water, where the current was too swift 

 for stratification. The shells are usually found in cross-bedded strata, showing 

 that they were placed in these deposits by the currents which moved the sand 

 and gravel. Many of these deposits probably represent dead and loose shells 

 which were picked up and moved along, but in a few instances they are found 

 in situ (as at Prospect Park) indicating that they lived on the spot where they 

 were buried. 89 Mollusks have been found at Goat Island, Prospect Park, 

 Whirlpool, and Muddy Creek on the American side; and at Queen Victoria 

 Park, Whirlpool, and Foster's Flats on the Canadian side. The comparative 

 distribution is expressed in the table shown on page 149. 



Similar material, consisting of large numbers of Unio shells in a soft and 

 fragile condition, was recently found in the city of Niagara Falls, in an excava- 

 tion in Falls Street, about 100 feet east of Prospect Street, at a depth of 9 to 

 10 feet. 90 



Of the species listed by Letson all but two are now living in western New 

 York, in the Niagara River, or in lakes Erie and Ontario. Fusconaja solida 

 is a Mississippi River species, not now living in the St. Lawrence drainage. 91 

 Pleurobema cocicneum appears to be referable to the form called magnalacustris , 

 which is not uncommon in the Niagara River. Amnicola letsoni was at first 

 described as an extinct species, but has since been found recently washed up 

 on the shore of Lake Erie in Monroe County, Michigan, and from the drift of 

 the Raisin River at Dundee, Michigan. Goniobasis livescens niagarensis 

 differs from the variety as found elsewhere in the persistence of the peripheral 

 keel in the adult stage. 



Just what relation this fauna may bear to the smaller Lake Tonawanda,* 2 

 which extended eastward up the valley of Tonawanda Creek for about fifty 

 miles, is not known; there seems to be no reason why a lake fauna, such as the 



« 8 Letson, Bull. Buff. Soc. Nat. Sci., VII, pp. 238-252; Kindle and Taylor, Niagara 

 Folio, No. 190, U. S. G. S., pp. 14, 19; Geol. Surv. Canada, Guide Book No. 4, p. 41. 



89 See Grabau, Bull. Buff. Soc. Nat. Sci., VII, pp. 61-68. 



80 Niagara Folio, p. 14. 



91 In Miss Letson 's list this species is given as occuring in the Niagara River. The writer 

 knows of no record from the St. Lawrence drainage. 



93 Kindle and Taylor, Niagara Folio, p. 19. 



