66 THE OLDEST ROCKS OF ENGLAND. CHAP. 



deposition of marine sands, now consolidated to stone, somewhat 

 peculiar in composition, and of a greenish, tint, as if derived from 

 decomposed rocks of the old Malvern types. Sometimes an appear- 

 ance is presented which has suggested the idea of volcanic ash, 

 erroneously as it appears to me. Occasionally small fragments and 

 pebbles occur which may be regarded as of Malvern origin. To 

 account for this deposit, suppose the old rocks to have been once 

 far more extended northward, and to have been wasted by atmo- 

 spheric and sea-action ; let the prevalent currents have been from 

 the north ; sand-banks would have been formed along the flanks 

 and round the south end of the hills ; and the loops may have been 

 continued to the eastern side, but that is concealed from obser- 

 vation. 



These sandbanks are the Hollybush sandstone. Its thickness 

 is not less than 600 feet ; it may be much greater, for its real base 

 is not seen ; there may be other strata below ; but we have no 

 means of discovery, or even of conjecture. It is poorly marked 

 by life remains : possibly fucoids ; certainly annellida and brachio- 

 poda. 



The following short list is given by Dr. Holl d : 



Annellida. Scolithus. 



Trachyderma antiquissima. Salter. 



Serpulites fistula. Holl. 

 Brachiopoda. Lingula squamosa. Holl. 



another species. 



OboleUa Phillipsii. Holl 



two other species. 



A small unascertained bivalve. 



This fauna has a very primordial aspect ; but so small a group 

 of fossils can hardly be held to prove more than general analogy 

 to some part of the Cambrian series of strata. The absence of 

 trilobites is remarkable. The catalogue will probably be augmented 

 by further search, but it must be a tedious search. 



The next great deposit, confined to the southern part of Malvern, 

 and following in a parallel loop the curve of the Hollybush sand- 

 stone, is a nearly uniform black shale, of great thickness about 

 500 feet e enclosing some bands of 'trap/ composed of felspar 



d Geol. Journal, 1865, vol. xxi. p. 89. 



Dr. Holl increases my estimate to 1000 feet. 



