552 Mr. Strickland on the Geology of the line 



domya ambigua, Modiola scalprum, Plagiostoma punctatum, P. duplicatum, Plicatula 

 spinosa, Spirifer Walcotti, Corbula cardioides (Phill.*), Amphidesma donaciforme 

 (Pliill.), Pecten sublrevis (Phill.), Ammonites' planicosta, A. obtusus, A. Turneri, A. 

 Conybeari, and A. Birchi, have been identified. Between Bredon and Cheltenham 

 the ground is very level, and but few sections of importance occur ; but at the 

 latter town, and between it and Gloucester, the excavations in the lias clay are 

 very extensive, and have supplied large collections of organic remains to the 

 cabinets of the Cheltenham geologists. 



Some of these fossils are enumerated in Mr. Murchison's memoir on the Geology 

 of Cheltenham, but a considerable number of species, especially of Ammonites, 

 appear to be new, as I have been able as yet to assign names to only the three 

 following: — Ammonites armatus, Sow., A. ovatus, Young and Birdf, and A. lenti- 

 cularis, Young and Bird. With the exception of the Hippopodium ponderosum, 

 Gryphaa Maccullochi, and one or two others, the Cheltenham fossils are wholly 

 distinct from those of Bredon, proving how small a difference of vertical position 

 will effect an almost total change of organic remains. At Hewlitts, east of Chel- 

 tenham, the lias near the base of the marlstone presents another series of distinct 

 fossils, consisting of Hippopodium ponderosum (rugose variety, perhaps a distinct 

 species), Modiola scalprum, Spirifer granulosus, Goldf., Terebratula rimosa, Bronn j, 

 Perna ventricosa, Pachyodon attenuatus, Stutchb., Littorina imbricata {Trochus 

 imbricatus. Sow.), Ammonites Henleyi (A. striatus, Rein., A. heptangularis. Young, 

 A. Cheltiensis, Murchison §), &c., so that in the lower lias alone we have evidence 

 of at least five well-marked successions of molluscous faunae ranging through a 

 vertical height of about 400 or 500 feet, and unaccompanied by any change in 

 the mineral character of the deposit. 



Having now described the secondary formations along the line of the railway, 

 we will recommence at the Birmingham end, and examine the deposits of superficial 

 detritus. 



The phsenomena exhibited by the railway cuttings are entirely confirmatory of 

 the views which I have announced elsewhere 1| respecting the distinction between 

 those ancient terrestrial alluvia in which mammalia occur and the general mass of 

 submarine drift which covers most parts of the island. In pursuance of these 

 views, the ancient superficial detritus of this district may be divided, according to 

 its efficient cause, into Jiuviatile and marine ; the latter, according to its origin, 

 into local and erratic ; and this again, according to its composition, into gravel with 

 flints and without flints. 



* Geol. Yorkshire, Part 1. -f- Geological Survey of the Yorkshire Coast, 4to, 1828. 



J Lethsea Geognostica, p. 292, Taf. 18, f. 6. 



§ Outline of the Geology of the neighbourhood of Cheltenham, 1834. 



II See Report of British Association, vol. vi. Sections, p. 61. 



