CAMBEIAN AND LOWEE ORDOVICIAN. 153 



division 'M, or 12, as previously given, and the lowest part of these additional strata are 

 considered equivalent to some of those at Point Rich. 



H. 



Feet. 



1. Bluish-gray limestone in beds of from 1 to 2 inches, inteistratified with gray subcryatalUne 



yellow-weathering magnesian hmeBtone in beds of from 3 to 6 inches thick. The beds 

 are fossiliferous, containing the genera Orthis, Ophileta, Maclurea, Pleurotomaria, ilxKchi- 

 sonia, Orthoceras, and Bathyurus. The described species are Orthis electro?, Maclurea 

 matutinaf, and Orthoceras piscator 100 



2. Strata concealed 165 



265 



Division I of Logan's classification was placed by Billings in the Chazy, with 

 some doubt, and is described in Chapter IV, together with divisions K to P inclu- 

 sive. (See pp. 211-217.) 



Billings ^^ classified the faunas and arranged them in a catalogue. Commenting 

 on their distribution and relations, he states: 



POTSDAM GROUP. 



In this group consisting of divisions A, B, and C, we have 19 species, none of which are 

 found in the Potsdam sandstone in Canada. But in that part of the group, which is usually 

 known, in the State of Vermont, under the designations of the Red sandrock and the Georgia 

 slates, the following occur: Scolithus linearis, Palseophycus incipiens, Obolus lahradoricus, OholelJa 

 (Kutorgina) cingulata, Olenellus thompsoni, 0. vermontarm, Conoceplmlites adamsi, and C. teucer. 

 As these are the most abundant species in the formation, both in Vermont and Newfoundland, 

 there can be little doubt but that the rocks in which they occur, in these two widely separated 

 localities, are of the same age. * * * Iq the next overlying strata, division D, Lingula 

 acuminata was found at Bay St. Barbes. I have compared the specimens from this locality 

 with those that occur so abundantly in the upper part of the Potsdam ia the township of 

 Beverly, in Canada West, and believe them to be perfectly identical. 



OALOIFEROtTS FORMATION. 



The Calciferous formation is represented in Newfoundland by all the divisions from D to 

 H inclusive. In this series of strata there are 63 species, of which the following 14 are found 

 ia Canada and New York: Stenopora fibrosa, Stromatopora rugosaf, Lingula acuminata, 

 Euchasma hlumenbacJiia, Pleurotomaria calpJiumia, P. calcifera, P. laurentina, Murchisonia anna, 

 EccuiiompTialus atlanticus, Orthoceras lamarcki, Piloceras canadensis, BatJiyurus cordai, Asaphus 

 canalis, and Leperditia turgida. Exceptiag S. fibrosa and B. cordai, all of these occur in the 

 true Calciferous in Canada. B. cordai abounds in the same formation in New York. 8. rugosa 

 is doubtfully determined and is probably distinct from the Black River species of that name. 

 The beds in which L. acuminata occurs in Canada are placed ia the top of the Potsdam; but as 

 Pleurotomaria canadensis and an orthoceratite are associated with it, perhaps these particular 

 strata should be more properly referred to the base of the Calciferous, and they would then 

 correspond to division D. Most of the species are found ia divisions G and H, the upper part 

 of the formation in Newfoundland. Two of the species {S. fibrosa and A. canalis) range upward 

 into the Chazy, the former continuing to the Upper Silurian. The general aspect of the fauna 

 is peculiarly that of the Calciferous, the most strikiag features being the great numbers of small 

 Maclurea and species of Piloceras, the latter a genus which seenas to have culminated ia this 

 particular period. 



