1863.] SALTER UPPER OLD RED SANDSTONE. 493 



stress on its union, as a formation, with the rest of the New York 

 series — the Portage, Hamilton, and other groups, which represent the 

 mass of the Devonian. It is covered (unconformably ?) by the 

 Catskill conglomerate, which there can be no doubt represents our 

 own Upper Old Eed, and therefore the Marwood series inclusively. 



§ 7. General Conclusions, 



If I have thus established clearly, by position, by intercalation 

 of marine beds with the red sandstone, and by fossils, the identity of 

 the uppermost Devonian or Marwood group with the Upper Old Red 

 (I must omit for the present the Petherwin group, which is also 

 probably, but not certainly, included in this upper division), it re- 

 mains to be seen whether the same great clue — the fossil evidence — 

 will suffice to give us the long-wished-for identification of the Middle 

 and Lower Devonian with the Middle and Lower Old Red Sandstone. 

 It is not difficult of proof. 



I hold that the masterly suggestion of Sir R. I. Murchison, that 

 the Caithness Flags, full of Coccosteus, Ptericlithys, and a dozen other 

 genera, belong to the Middle, and that the Cephalaspis-beds of 

 Scotland belong to the Lower Division of the Old Red, is the great- 

 est advance made of late years in the classification of the British 

 Devonian rocks. 



Without this clue we were in a sea of difficulties and contradic- 

 tions. But, following it out, the whole of the Old Red Sandstone 

 subdivisions fall into their proper places, and can be correlated ac- 

 curately with the Continental equivalents*. 



Thus, in Russia, the Eifel, and the Hartz, Coccosteus, the cha- 

 racteristic Fish of the Middle Old Red beds, is found associated 

 with the fossils of the Eifel or Middle Devonian limestone. In 

 Russia, Sir Roderick Murchison informs me, they have been found 

 by his friends in the same slab. The identity of this part of the 

 two formations is thus proved, and need not further be discussed. 



But what of the Cephalaspis-beds or Lowest Old Red ? And how 

 are we to identify them with the Lowest Devonian, the Coblentzian 

 or Rhenane series ? 



Professor Ferd. Rcemerf and Professor Huxley X have unexpect- 

 edly answered this question for us. The former obtained a fossil 

 which he supposed to be a naked Cephalopod, allied to the Sepia, and 

 which he described as Archceoteutliis Dunensis in the * Palaeontogra- 

 phica' and the ' Jahrbuch.' It came from the Lower or Coblentzian 

 rocks of Daun. Afterwards it was again obtained from Wassenach, 

 on the Laacher-see, Lower Eifel. There is no doubt whatever that 



* "While these pages are writing, Sir Roderick has received specimens, ob- 

 tained by Mr. C. Peach, from the beds which rise out from under the Caithness 

 flags, at Ulbster Wick. They prove to contain specimens of the Pterygotus- 

 type, and are most satisfactory as proving the succession to be what was before 

 indicated. See Prof. Eamsay's Anniversary Address to the Geological Society, 

 Quart. Jo urn. Geol. Soc. vol. xix. p. xlv. 1803. 



t Palreontographica, vol. iv. p. 72 ; Leonhard and Bronn's Jahrb. 1858, p. 55. 



+ Quart. Jo urn. Geol. Soc. vol. xvii. p. 163. 



