434 



P. B. BEODIE ON CERTAIN QTTAKTZITE AKB SANBSTONE 



probable source of the Budleigh pebbles which contain fossils of 

 that date. The extension of this area of ancient rocks, or, indeed, of 

 any geological age, is never improbable when we consider the 

 enormous amount of denudation which all great formations have at 

 one time or other undergone. I have made some additions to 

 the Lower-Silurian fossils I have detected in the Warwickshire Drift 

 since the publication of my former paper on this subject in the 

 Journal of the Geological Society (vol. xxiii. p. 210, 1867); Orthh 

 redux and Lingula Leseuri were determined by Mr. Woodward some 

 ■years ago ; Lingula, n. sp., by Mr. Davidson, and the remainder by 

 Mr. Etheridge, who has been kind enough to examine them ; and I 

 here give the entire number, with the additional species, on his 

 authority : — 



Or this budleigh ensis. 



Valpyana. 



Lingula Leseurii, n. sp., 

 Spirifer antiquissiinus ? 



Davidis ? 



Rhynchonella sp. 

 Modiolopsis lirata. 

 sp. 



Davidson. 



Lyrodesma cselata? 



Ctenodonta Bertrandi ? 



Area Noranjoana ? 



Palaaarca secunda. 



Tracliyderma serrata, 



Calymene Tristani. 



Homalonotus, portions. 



Fucoids, one or two branching forms. 



Orthis budleigliensis is very abundant and characteristic. One 

 of the Lingulce determined by Mr. Davidson is, he says, a new 

 species and totally unlike any of those from Budleigh. The 

 Annelid Tracliyderma serrata is frequent and generally in good 

 preservation. The total number of Lower-Silurian genera and species 

 figured and described by Salter from the pebbles at Budleigh Sal- 

 terton is twenty-four ; and there are several diligent collectors of 

 these fossils in Devonshire. From the Midland Drift, in a limited 

 space and with less facilities for obtaining them, I have procured 

 sixteen, leaving only a difference of eight in favour of Devon — which 

 is somewhat remarkable, considering the much better opportunities 

 for collecting them in the West. At present, I believe, this is the 

 largest number of Lower-Silurian fossils of the age, probably, of the 

 Bala and Lower Llandeilo formations, hitherto observed in the Mid- 

 land Drift. This fact too, I think, strengthens my argument in 

 favour of more extensive ramifications of old palaeozoic rocks in a 

 north or north-easterly direction; and these, when broken up, would 

 furnish ample materials coming from different areas to supply the 

 fossiliferous pebbles referred to. No doubt this list would be 

 largely increased if the road-heaps, collected chiefly from the fields, 

 could be more diligently searched; for many fossiliferous pebbles 

 must be overlooked. 



Mr. Walter Keeping, in an interesting paper * on the Upware and 

 Potton Greensand pebble-beds, observes that " some of the quart- 

 zites are like those of the New Red Sandstone pebble-beds, and were 

 probably thus derived." He accounts for the presence of other older 

 palaeozoic pebbles by the supposition that they were derived from a 

 great palaeozoic ridge extending northwards towards Cambridge. 



* Geological Magazine, No. 195 (New Series, No. 19), Sept. 1880, p. 414. 



