GEOLOGY OF THE PHILIPSBURG REGION OF QUEBEC 2>2>2> 



town in this region. Here the Lower Chazy rests upon Division 

 E, which is poorly represented but can be correlated with the lower 

 part of Division B5 at Philipsburg. It is proposed here to include 

 in the Middle Beekmantown all the strata predominantly of massive 

 limestone and dolomite above the transition beds of the Lower 

 Beekmantown, and below the shale and limestone conglomerate 

 beds of the Upper Beekmantown. The advent of the Middle 

 Beekmantown according to this division is sharply marked by the 

 appearance of OphUeta complanata, and the close is equally sharply 

 marked by the occurrence of a typical gastropod and cephalopod 

 fauna. Like the Lower Beekmantown, the Middle is predominantly 

 calcareous and dolomitic, while the Upper is characteristically 

 shaly. It is perhaps not necessary here to enter upon a detailed 

 comparison of the fauna of the Middle Beekmantown but merely 

 to note the presence of a fauna assemblage in Divisions D5 and Ci 

 at Philipsburg which is very similar to that found at the top of Di 

 at East Shoreham and known as the "Fort Cassin fauna." This 

 marked zone of gastropods and cephalopods can serve as a general 

 indication of the top of the Middle Beekmantown. Occupying 

 approximately the same horizon in both localities and being domi- 

 nated by thick-shelled representatives of such genera as Murchisonia, 

 Holopea, Cyrtoceras, Ecculiomphalus , Maclurea, Euomphalus, 

 Raphistoma, Lophospira, and Orthoceras, there is a marked simi- 

 larity generically between specimens from the two provinces. 

 Lithologically also the rocks are quite similar. 



UPPER BEEKMANTOWN 



It is proposed to include in the Upper Beekmantown all strata 

 between the massive beds carrying the Fort Cassin fauna and the 

 Chazy unconformity. In the Philipsburg region this consists of 

 an unknown thickness of closely folded slate with intercallated 

 lenses of limestone conglomerate. Near Mystic Station in one of 

 these conglomerate outcrops, a fauna was collected by the writer 

 which differed markedly from the typical Upper Beekmantown 

 fauna of this region. It is possible that the Normanskill has been 

 infolded at this locality. The Upper Beekmantown must, of neces- 

 sity, be indefinite because of the erosion which followed its deposi- 



