UPLAND SOCIETIES OF PETOSKEY-WALLOON LAKE 



REGION 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 256 



H. D. Clayberg 



(with one figure) 



Introduction 



The writer became familiar with this region through spending 

 the summers there for the past 12 years. During this time the 

 rapid destruction of the few wild areas left suggested that studies 

 be made while natural remnants were still available. The observa- 

 tions on which this paper is based have been carried on for at least 

 three years. Besides the general data, 40 quadrats were made and 

 a map of the plant geography (to be published later) was drawn. 



The topography of this area was largely determined during the 

 Pleistocene and Postglacial. Leverett and Taylor (16, 17) have 

 covered thia phase ably. At the time of the formation of Lake 

 Chicago beaches this region was ice-bound, later forming part of 

 the submersed area which gradually emerged as the waters changed 

 from Lake Algonquin to the Nipissing Great Lakes, and through 

 the Post-Nipissing stages to end in Lake Michigan. This periodic 

 subsidence left the Algonquin, Nipissing, and later beaches (to- 

 gether with scattered morainal lakes inland), but erosion here has 

 eaten away much of the Post-Nipissing levels. 



The region at present is underlaid with Devonian deposits. 

 Inland the surface layer is Upper Devonian, being largely black 

 Antrim shale; while a marginal strip of about 3 km., from Petoskey 

 west, and all territory north of the south margin of the Inland 

 Route are covered with Middle Devonian. The latter contains the 

 Petoskey limestone, which outcrops along the shore of Little Trav- 

 erse Bay, either as shelving bedrock or limestone cliffs, the beds 

 dipping inland. The lakes and channels have a layer of sub- 

 aqueously deposited sand, covered in most places by black muck 



Botanical Gazette, vol. 69] 



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