82 PROCEEDINGS OF THE NATIONAL MUSEUM vol.76 



formations further comment is regarded as unnecessary because the 

 statement and braces on the chart give a sufficiently clear illustra- 

 tion of my belief that the formations and zones of this age in the 

 northeastern St, Lawrence extension of the Appalachian Valley 

 region fall between rather than opposite the formations in its 

 southern part (see pp. 57 and 76). The Lowville and the in part 

 sandy shales (Snake Hill, Canajoharie, and Schenectady), that are 

 correlated with the lower half of the Martinsburg occur in the 

 Champlain and lower Mohawk valleys. The Richmond, Alexandria, 

 and Clinton formations at the top of the column occur on the Island 

 of Anticosti. 



In 1923 ^^ I referred the Gun River formation of the Anticosti 

 section to the Lower Clinton. This was done on unimpeachable 

 fossil evidence found on slabs that had been sent by Doctor Twen- 

 hofel to Doctor Bassler for report on the Bryozoa and Ostracoda 

 and which were marked as collected by the former in the Gun River 

 formation. Twenholfel's final report ^* on the " Geology of Anti- 

 costi Island " now being at hand it appears that these supposed Gun 

 River fossils were either incorrectly labeled or the beds from which 

 they were collected were subsequently assigned to the lower part of 

 the Jupiter River formation. Despite the elimination of these un- 

 questionably Lower Clinton fossils review of the revised lists of 

 Gun River fossils in Twenhofel's last report still leaves considerable 

 and perhaps sufficient ground for my 1923 view. At present, there- 

 fore, I will modify it only so far as to say that the Gun River is 

 mainly and perhaps entirely of Clinton age. The underlying Becsie 

 I regard as either contemporary with the Brassfield or slightly older 

 but not as old as the Edgewood of Missouri and southern Illinois. 

 The Ellis Bay falls somewhere between two or opposite one of the 

 three or four Upper Medinan formations that underlie the Brass- 

 field in the Mississippi Valley. Partly to indicate the uncertainty 

 of these correlations — but mainly because alternate arrangement of 

 the units accords with my view that, as a rtile, formations in the 

 eastern part of the St. Lawrence trough are not precisely correlat- 

 able with those of nearest dates in interior basins — the Gun River 

 is placed midway between the Clinton and the Brassfield and the 

 Becsie just beneath the space alotted to the Brassfield. 



Britain. — This column begins with the Tremadoc, which I believe 

 belongs rather low in the Canadian and may be correlated in general 

 with the Dictyonema fldbelliformis zone of the Bretonian of Matthew 

 and the Schaghticoke shale of eastern New York. The Shineton 



"Ulrich, E. O., and Bassler, R. S., American Silurian formations: Maryland Geol. Sur- 

 vey, Silurian vol., pp. 368-372. 



»«Geol. Survey Canada, Mem. 154, 1928 (tiUe page reads 1927). 



