240 Correspondence. 



To the Editor of the Geological Magazine. 



Deak Sir, — ^I have two or three new palEeontological facts to com- 

 municate, and I do not wish to keep my brother palasontologists 

 waiting till I shall have leisure, which like " to-morrow, never 

 comes." 



Imprimis. — The earKest trilohite we know in Britain, is not 

 Paradoxides, as usually supposed; it is a large and well deve- 

 loped species of Conocoryphe, G. bufo, which will be figured by 

 Mr. H. Hicks and myself in our forthcoming work on " The Geology 

 of St. Davids." 



2. The Arenig and Skiddaw group of Sedgwick, long known, but 

 only lately defined by its fossils, is disclosing in various ways its 

 fossil contents, and is imequi vocally the representative of the Stiper 

 Stones series, which Murchison, in his last edition of Siluria, iasisted 

 on considering as the true Lingula flags. 



I have every reason to believe too, and shall give you my reasons 

 for so thiiaking, shortly, that the anomalous fauna of the French 

 Silurians of Angers and Brittany generally, is to be referred to this 

 date ; and in all probability the " Budleigh Salterton," excluding its 

 mixture of Devonian forms, is referable to this important period also. 

 My first suggestion is thus refuted : for I thought it, in the paper 

 you did me the honor to print,' the equivalent of our Llandeilo, or 

 possibly our Lower Llandovery rock group. 



3. The Lower Llandovery, or as I prefer to call it with Prof. 

 Phillips the ''Llandovery rocks," are intimately united with the Cara- 

 doc, and pass up from them with a great admixture of Lower Silu- 

 rian, not Upper Silurian forms. The May Hill Sandstone, on the 

 contrary, as Sedgwick showed in 1853, is as unequivocally the base of 

 the Upper Silurian, and contains scarcely any true Lower types. 



4. The Downton Sandstone is the natural top of the Ludlow series, 

 and is quite distiuct from the " Passage beds," of Murchison, which I 

 have for some time called the " Ledbury shales." In the Downton 

 rock of Kington, Herefordshire, my friend, Eichard Banks, Esq., has 

 for more than two years, I think, discovered the tracks of an animal, 

 which, in your June number I hope to show, is the track of Pteraspis, 

 our oldest fish. I owe it to Mr. Banks, who gave me the specimens, 

 unique they are at present, to withhold his discovery no longer. The 

 fish had apparently a bony crutch or spine in advance of the pecto- 

 ral fin, and the tracks are accordingly double, on each side. 



I am, Dear Sir, truly yours, 



J. W. Saltek. 

 April 16, 1866. 



I will only add that, with respect to the Devonian controversy, 

 our excellent field geologist. Prof. Harkness, having lately visited 

 Devon, has returned, convinced that the Devon rocks are all sub- 

 •iarbohiferous. — J. W. S. 



1 Geol. Mag., 1864, Vol. I., p. 5. 



