STATE GEOLOGIST. 65 



fer grrgaria. Meridtt, Cyrtia, (n. sp ) Acrrvularia Davidsoni 



(from the limestones separating the Belderberg and Hamilton 



Groo] inmeroai other fossils. From other parts of the 



up has furnished a Bellerophon, (n. sp.) Spirifer 



ul(rijuga(v.<, ) S>jrin<; ProductU9$ 



Atn/na rtticul v >mnia rugosa, Spirifer duodenaria, 



homena ) ■ >■(!. Atryp* > n. >■/< § r (peculiar for 



ition in mesial sinus) S tp.) MeritUila, ( N. 



Y. R .».) and many other forma. 



The formation is extensively u 1 by divisional planes; 



and even in those portions not belonging to the breceiated mass 

 at Mackinac, ia apt ta-be conaiderably broken up. The open 



•tor of the rook j ermita the escape of numerous copious 

 spriu _ sh water, and occasionally gives rise to the sud- 



den d -'.reams and lakes. Various accounts are 



current, in Monroe county, of subterranean communications 

 from lake to lake, and even between Lake Erie and the western 



f the county. I heard it repeatedly stated, that at cer- 

 tain n of the year, Ottawa La: i off by some 

 subterranean outlet causing the death of all the fish which 

 remain, but that, on the refilling of the lake, the water is always 

 accompanied by a fresh stock of fish. ln # Mr James Cummins' 

 quarry, about live miles, in a rig-lit line, north-east of Ottawa 

 Lake, the rock is d I as cavernous and full of sink holes; 

 and what is remarkable, is the fact that this quarry is always 

 filled with water when the lake is high, and empty when it is 

 low; and whenever the quarry is full, it contains bass and dog- 

 fish of the common species of that region. 



The curions, suturedike structure so often referred to by 

 - frequently met with in Michigan — two con- 

 rock being studded, on their contact snrfacea 

 with tooth-like or prism like processes which fit into correspond- 

 ing pits on the f black bituminous 

 matter generally prevents a perfect - f the contiguous 

 surfa. ;. veloped, 



