202. Sir TV. E. Logan on the Quebec Groups Sfc^ 



on Campment d'Ours is of the same color and friable character 

 as the yellowish-white beds near Marquette and is marked by the 

 same Scolithus, and there is little doubt that the two exposures are 

 of the same series. On Campment d'Ours the sandstone reposes on 

 the Huronian series ; it is eighty feet thick and is very nearly 

 horizontal, (fig. 2.) It is succeeded in ascending order by the 

 following series of beds : — 



Bluish-gray shales interstratified with thin beds of yellowish 

 compact limestone, presenting an escarpment over the sandstone ; 

 the fossils observed are Stenopera fibrosa, Ftilodictya fenestrata, 

 P. acuta, StropTiomena alternata, Rhynconella plicifera, and a 

 small undetermined Lingula 20 



Measures concealed 60 



Ash-gray compact limestone in beds of from three to five inches 

 thick, interstratified with a five-inch bed of drab colored compact 

 hmestone ; among the fossils are Stenopera fibrosa, Glyptocrinus 

 ramulosus, Strophoniena alternata, Pleurotomaria subconica, Subu- 

 tiles elongatus, Amboni/ehia amygdalina, Cyrtodonta Suronensis, 

 Vanuxemia inconstans, Orthoceras tenuifilum, O. Murrayi, Leper^ 

 ditia Canadensis, and Asaphus platycephalus 4 



Ash-gray compact limestones in beds of from four to six inches, 

 underlaid by a dark brownish-gray arenaceous limestone bed of 

 about ten inches, and divided by thin layers of gray calcareo- 

 argillaceous shale ; all the strata are very fossiliferous, and the 

 species they contain are Glyptocrinus ramulosus, Ftilodictya mul- 

 tipora, Coseinium fiabellatum, StropJiomena alternata, S.filitexta, 

 Rhynconella reeurvirostra, Orthis subequata, Vanuxemia incon- 

 stans, Cyrtodonta Hiironensis, G. suhcarinata, Pleurotomaria sub- 

 conica, Trochonema umbilicata, Murchisonia perangulata, Orthoce- 

 ras recticameratum, Cheirurus pleurexanthemus, and Leperditia 

 Canadensis 30 



Ash-gray compact limestone of the same character as the preced- 

 ing, but still more fossiliferous ; the beds contain Tetradium 

 fibratum, Stenopora fibrosa, Columnaria alveolata, Petraia pro- 

 funda, Strophomena alternata, S.filitexta, Rhynconella reeurviros- 

 tra, Ambonychia amygdalina, Cyrtodonta Canadensis, C. Huronen- 

 sis, C. mytiloidea, Vanuxemia inconstans, Ctenodonta nasuta, 

 Pleurotomaria subconica, Eunema strigillata, Subulites elongatus^ 

 Orthoceras tenuifilwn, O. Murrayi, an undescribed Cyrtoceras, 

 Asaphus platcycephalus, and Leperditia Canadensis 16 



130 



The fossils of these limestones leave little doubt that they be- 

 long to the Birdseye and Black River group, and the underlying 

 sandstones and other rocks, constituting the upper copper-bearing 

 series of Lake Superior, may thus represent the Chazy, Calciferous, 

 and Potsdam formations and be equivalent to the Quebec group 

 and the black shales and limestones beneath. 



