462 THE CANADIAN NATURALIST. [Vol. X. 



fossils indicate a second graptolitic zone, possibly older than that 

 which afforded the species described by Hall. 



At Matane Mr. Richardson has found a bed of highly laminated 

 black shale similar to that explored by Mr. Weston a few years ago 

 at Little White River, holding similar fossils in great abundance. 

 Prominent amoug them is a beautiful Dlctyonema, distinct from 

 any of these found at Levis, and which on comparison with speci- 

 mens presented to the Museum by Prof. H. Allejne Nicholson, 

 appears so close in all its characters to D. sociale Salter, of 

 the English Tremadoc, that it may fairly be assumed to 

 represent that species in our fauna. It is well known that 

 some good palaeontologists regard D. sociale as only varietally 

 distinct from D. flahelliforme oi ^'ichvfM from Russia; and the 

 Norwegian species known as D. Korvegicwni and D. graptoli- 

 thinum are also regarded as varieties of the same species, which 

 in all these countries seems characteristic of the upper Cambrian 

 beds.^ We might infer from this that the Dictyonema beds at 

 Matane may indicate a horizon somewhat lower than any of those 

 at Levis. Associated with the Dictyonema are many specimens 

 of Didymograptus flexilis and D. Logani^ or an allied form, and 

 there are also fragments of an undetermined Tetragraptus. In 

 a neighbouring bed there is a vast quantity of debris of Trilobites, 

 and though these are all in a very fragmentary state, yet such 

 specimens as give any indications of the genera to which they 

 belong, would seem to agree with the graptolites in indicating 

 an Upper Cambrian age. They are apparently more nearly 

 related to the trilobitic fauna of the Potsdam of Newfoundland, 

 as described by Billings, than to that of Levis. 



It is no doubt true that organisms like graptolites, which have 

 a great range both in time and space, are not so much to be relied 

 on as some other fossils in determining subdivisions of formations. 

 Yet there seems reason to believe from Mr. Richardson's recent 

 observations that graptolitic zones reaching from the Lower 

 Tremadoc to the Upper Llandeilo may be discriminated in the 

 great mass of sediments known as the "Quebec Group," which 



vertical stems being slender and as many as 18 in a centimetre. 

 Cells in one series, round in cross section ; aperture pointed, but 

 apparently not mucronate ; transverse bars very slender, more distant 

 than the vertical stems but constituting a distinct network. 



* Dr. Schmidt in Journal of Geological Society of London, Nov., 1882- 



