POSTGLACIAL BIOTA OF THE GREAT LAKES REGION 



135 



Eurynia iris ( = novi-eboraci) 



" cllipsifonnis( = spatidatus) 

 Lampsilis ventricosa 

 Spttaerium simile{ = sulcatum) 



" striatinum 

 Pisidium near abdilum 



" compression 



" medianum 



" milium 



" pauperculum 



" roperi 



" nentricosum 



" near vesiculare 

 Campeloma integrum 



" integrum obesum 



" subsolidum 

 Head of dipterous insect 



Physa ancillaria 

 " Integra 

 " heterostropha 

 A ncylus rivularis 

 Planorbis antrosus{ = bicarinatus) 



" campanulatus 



" trivolvis 



" deflectus 



" parvus 

 Galba obrussa (=desidiosa, authors) 



" humilis modicella 

 Lymnaea stagnalis appressa 

 Carychium exiguum 

 Succinea ovalis 

 Strobilops labyrinthica 

 Vitrea hammonis (=radiatula) 

 Mammut americanum 



Considerable drift wood was observed, but none was identified. The shells 

 occur in little colonies, just as they are found today. It is probable that these 

 colonies represent localities where the water had brot together and deposited a 

 quantity of dead shells, drift wood, and other debris, and not colonies of living 

 mollusks. The mastodon skulls were found in and under the stratum of semi- 

 ligneous peat, showing that these animals waded into the river after the shells 

 were deposited. They were probably caught in the boggy marsh and drowned. 



3. Lake Algonquin 



In Fairhaven Township, Huron County, in a bog near the corner of sections 

 26 and 27, sands occur which lie at an elevation of a little more than 20 feet 

 above the lake level (605 feet above tide). On the north side of section 34, 

 deposits occur which are thot to be fragments thrown up on the beach. They 

 are somewhat higher than the deposits previously mentioned. Both are re- 

 ferred to the Lake Algonquin stage. The molluscan remains in these deposits 

 are tabulated below: 



Elliptio gibbosus 

 Sphaerium striatinum 

 Pisidium contortum 

 Goniobasis livescens 

 Amnicola limosa 



Campeloma species 

 Planorbis campanulatus 



" deflectus 



" antrosus ( = bicarinatus) 



Extensive deposits occur in Bay "County which contain much biotic mater- 

 ial M Several of these are referable to the Lake Algonquin stage. "Near the 

 northeast comer of section 33, near Monitor, is a depauperized fauna in a sandy 

 loam deposit containing cobble stones. The she Is are well preserved. The 

 area was occupied by a swamp land formed back of the Algonquin beach to 



M Cooper, Rep. State Board Geol. Surv. Mich., 1905, p. 353. 



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