404 Prof. Sedgwick on the New Red Sandstone Series in the 



The discussion on the age of the Caithness schists might now be con- 

 sidered unnecessary ; but when the paper was read, there were many mem- 

 bers of the Society who were disposed to identify them with the ichthyolites 

 of Mansfeld. The question is now set at rest by the generic and specific 

 characters of the Caithness fossils, and by the discovery of fossil fish in the 

 old red sandstone of Herefordshire, identical with specimens found in the old 

 red sandstone of Scotland. 



Were I to make any change in the Caithness section, published by Mr. 

 Murchison and myself*, I should alter the colour of the sandstone of Dunnet 

 Head, and make it of one tint with the lower conglomerates ; thus including 

 the highest beds of the series in the old red sandstone. The formation would 

 then have three divisions, which might be respectively compared with the 

 three divisions of the Herefordshire sandstone, first given by Dr. Buckland 

 and Mr. Conybeare ; and the ichthyolites of Caithness would then come on 

 the same parallel with the cornstones of Herefordshire, 



If such a comparison be considered as too refined for the evidence on which 

 it rests, I may at least assert, that the words "newer red sandstone," placed 

 under the colour representing the group of Dunnet Head, tend only to mis- 

 lead the reader, and do not correctly represent our opinions at the time the 

 section was publishedf . By these words, English geologists have generally 

 designated deposits of the age of the upper sandstone of St. Bees Head, with 

 which it was never our intention to bring the rocks of Dunnet Head into com- 

 parison;];. It is true, that the upper limit of these rocks must remain ni some 

 measure ambiguous ; but 1 have now little doubt that the whole of them ought 

 to be classed with the old red sandstone. 



The relations of the red sandstone group of Shropshire to the carboniferous 

 series have been described during the past year in great detail by Mr. Mur- 

 chison ; and I believe his views agree perfectly with what is stated above 

 (pp. 399, 400.). I had few details to offer, and only alluded to the Shropshire 

 formations for the purpose of confirming conclusions drawn from certain 

 phaenomena in the North of England. 



and Flintshire. How many terms of the series are wanting it is impossible to tell without more 

 evidence ; but this evidence is given in the Shropshire and Herefordshire sections described by 

 Mr. Murchison. 



* Geological Transactions, Second Series, vol. iii. Plate XIV. fig. 2. 



t I am the more anxious to make this correction, because Mr. Conybeare has adopted and ex- 

 tended this error in his Memoir on the Progress of Geological Science, published in the first volume 

 of the Reports of the British Association for the Advancement of Science. 



J Geological Transaction?, Second Series, vol. iii, pp. 157, 1.58. 



