338 THE CANADIAN NATURALIST. [Vol. ix. 



Platyceras^ allied to P. jyyramidatum, Hall. 

 ^ Orthoceras exornatum, Dawson. 



0. Pictoense, n. s. (see infra). 



0. elegantidum^ Dawsou. 

 ^ Beyrichia pustulosa, Hall. 



Acidaspis, a small species allied to A. tuherculata of Hall 

 (see infra.) 



lUcenus. — pygidium . 



In the second edition of Acadian Geology, 1868, the author 

 published a list of fossils, including many of the more character- 

 istic species above-named, and summed up his conclusion as to 

 their age, as follows : " On the whole I regard the beds seen on 

 the East River of Pictou as belonging to the same line of out- 

 crop with the Arisaig series; but as probably containing in 

 addition to the Upper member of that series beds somewhat 

 higher in position," The fossils more recently collected so far 

 modify this conclusion that I cannot affirm the existence of beds 

 upward as far as the Oriskany, but must be content to regard 

 the hiofhest fossiliferous beds of the East River Silurian as about 

 .the horizon of the highest of those seen at Arisaig. 



It still remains to inquire as to beds older than the Upper and 

 ^Middle Arisaig series. As to these great caution is necessary, 

 owing to the paucity of fossils, and to the liability to confound 

 the Upper Silurian rocks with those of the Cobequid group. 



Coming up in the anticlinals, and along the flanks of the 

 masses of older rock, there are beds of conglomerate, brown and 

 white quartzite and hard slates, which seem to underlie the fossil- 

 iferous beds holding the iron ores, and may represent lower 

 members of the Upper Silurian series. In these beds vermicular 

 markings, perhaps fucoidal and perhaps burrows of annelids, 

 occur near Cameron's brook, and in the same beds are fragments 

 of Linguhe. I have little doubt that these beds are lower than 

 those holding the iron ores, though probably not below the base 

 of the Upper Silurian. On McLellan's Brook, Mr. Fraser has 

 found beds holding casts of Zaphrentis, which may not improb- 

 ably be older than the Lower Helderberg. The tail of lUcenus 

 referred to above was found in a small ore-bed on the Fraser 

 (Saddler) location, and which I believe to be not improbably 

 lower than the great beds of Hematite. These are the only fossils 

 known to me at present, which indicate a horizon older than 

 the Middle Arisaig. There a;e, however, great masses of 



