8 



cent Silurians ; but has, on the contrary, the very closest affinity with that of the Corniferoua 

 limestone above. Indeed, this is really understating the case ; since the fauna of the Oriskany 

 Sandstone of Canada is, with very few exceptions, identical with that of the Corniferous lime- 

 stone. All the typical and characteristic forms of life in the former pass up into the latter, 

 and it is thus impossible to draw any palseontological line of separation between them. Nor, 

 again, can it be said that there is any very close relationship between the fauna of the Oriskany 

 Sandstone of New York and that of the formation so-called in Canada. It is true, Mr. Billings 

 enumerates (Geology of Canada, p. 360) amongst the organic remains of the latter, such cha- 

 racteristic fossils of the former as Rensselaeria ovalis, R. ovoides, Spin/era arenosa, Spirifera 

 airecta, and Orthis musculosa. As a more than sufficient set-off, however, against the resem- 

 blance thus established, is the fact that the Oriskany Sandstone of Canada is crowded with 

 the remains of corals, such as F. Gothlandica, F. hemispherica, F. turbinata, F. polymoipha, 

 &c., which are characteristic of the Corniferous limestone, whilst the Oriskany Sandstone of 

 the State of New York appears to exhibit a total and singular absence of corals. The former 

 deposit also contains numerous Trilobites and Brachiopods (such as Proetus crassimarginatus, 

 Dalmania selemtrus, Strophomena inequistriata, S. perplana, S. ampla, S. demissa, Chonetes 

 hemispherica, Chonetes mucronata, Athyris spirifer aides, Centronella ylans-fagea, Pentamerus 

 aratus, &c., which are not known to occur in the Oriskany Sandstone of the State of New 

 York, but which are characteristic forms in the Corniferous limestone. 



From a consideration of the above-mentioned facts, it seems evidentjjthat, whatever may 

 be the true position of the Oriskany Sandstone of the State of New York, the formation which 

 is so named in Canada clearly appertains to the Devonian system, of which it forms the natural 

 base. The question, indeed, arises whether the deposit which has been identified in Canada 

 with the Oriskany Sandstone may not rather be in reality the representative of the Schoharie 

 Grit ? On this question my own researches have been too slight to justify me in hazarding 

 any positive opinion. In the descriptions which follow, however, I shall make no distinction 

 between the Oriskany Sandstone of Canada and the Corniferous limestone, but shall regard the 

 two deposits as palaeontologically indivisible. No inconvenience can arise from the adoption 

 of this course here, as I have myself detected no fossils in the so-called Oriskany Sandstone 

 which I have not also recognised in the overlying Corniferous limestone, and I have, there- 

 fore, to describe no forms of life as peculiar to the former deposit. I would only add, to pre- 

 vent misconception, that I fully recognise the distinctness of the Oriskany Sandstone of New 

 York as an independent formation, and that, so far as my own studies have led me, I decid- 

 edly lean to the view advocated by Hall, namely, that the Oriskany Sandstone should be pro- 

 perly regarded as belonging to the Silurian system and not to the Devonian. 



II. CAUDA-GALLI GRIT. The Oriskany Sandstone, in the State of New York, is over- 

 laid by a series of beds of arenaceous shale, argillaceous sandstone, or slaty grit, with a maxi- 

 mum thickness of sixty to seventy feet, and almost devoid of organic remains. These are 

 known as the "Cauda-Galli Grit," from the presence in them of a peculiar spiral fossil sup- 

 posed to be the remains of a sea-weed, and they have yielded as yet no other fossils except 

 the problematical bodies just alluded to, and a single specimen of a species of Platyceras. As 

 before remarked, Prof. Hall is disposed to regard the Cauda-Galli Grit as the true base of 

 the Devonian series of North America. No representative of the Cauda-Galli Grit has as 

 yet been made out in the Devonian formation of Western Canada. 



