376 Geological Society : — 



April 6, 1859.— Prof. J. Phillips, President, in the Chair. 

 The following communication was read : — 



" On the Subdivisions of the Inferior Oolite in the South of 

 England, compared with the Equivalent beds of the same formation 

 on the Yorkshire Coast." By Thomas Wright, M.D., F.R.S.E. 

 (Communicated by T. H. Huxley, Esq., Sec. G.S.) With a Note 

 onDundry Hill, by R. Etheridge, Esq., F.G.S. 



The author first remarked that, since the publication of his me- 

 moir " On the so-called Sands of the Inferior Oolite" in the 

 Society's Journal (vol. xii. p. 292), some geologists, both in England 

 and on the Continent, had taken the Liassic character of these sands 

 into consideration, and that Oppel, Hebert, Marcou, and Dewalque 

 had agreed with the author on palaeontological grounds, whilst in 

 England Mr. E. Hull (of the Geological Survey) had also adopted 

 his views. On the other hand, in recent memoirs, Mr. Lycett re- 

 gards them as forming a distinct stage, and Prof. Buckman still re- 

 tains them in the Inferior Oolite. 



Dr. Wright then described the beds at Bluewick, on the Yorkshire 

 coast, which he regards as the equivalents of the " Cephalopoda- 

 bed" or " Jurensis-bed :" namely some shales and sandstones un- 

 derlying the rock which' he considers to be the basement-bed of the 

 "Dogger" or Inferior Oolite. 



These are — 1. (uppermost) Shales with Terebrattda trilineata, 

 Belemnites compressus, B. iri'cgularis, and Trigonia Ramsayi. 2. Sand- 

 stone, yellow, with Turritella, Trigonia, Astarte, Ammonites con- 

 cavus, A. variabilis, &c. 3. Yellow Sandstone or Serpula-bed. 

 4. Grey Sandstone or Lingula-bed, with Lingula Beanii, Orbicula, 

 Belemnites compressus, B. irregularis, Ammonites Moorei, &c. 



The author then observed that the Inferior Oolite in the South 

 of England admits of a palaeontological subdivision into three zones, 

 having the Fuller's Earth with Oslrea acuminata above, and the 

 Cephalopoda-bed with Ammonites opalinus beneath : — 1st (upper- 

 most), the zone of Ammonites Parkinsoni ; 2nd, zone of Am. Hum- 

 j)hriesiaHus ; and 3rd, zone of Am. MurchisoncB. He then described 

 the lowest of these zones, that of Am. Murchisonte, giving as syn- 

 onyms "Dogger" (part), Young and Bird, and Phillips; "the 

 Central and lower division of the Inferior Oolite," Murchison ; 

 " Fimbria- stage of the Inferior Oolite," Lycett ; " Brauner Jura/3," 

 Quenstedt ; " Calcaire laedonien" (part), Marcou; " Calcaire a en- 

 troques," Cotteau ; "die Schichten des Am. Murchisonse," Oppel. 

 The Leckhampton section was then described, as illustrating this 

 zone, which was also described in its details as seen at Crickley 

 Hill, near Cheltenham, and at Beacon Hill ; also at Frocester Hill 

 and Wootton-under-Edge. 



The preceding sections exhibit the lithological character and 

 stratigraphical relations of the Pea-grit and Freestones, which, how- 

 ever, undergo great and very important modifications when examined 

 over even a limited area, — the Pea-grit as regards its structure ; 

 and the Freestone, its thickness. In the Southern Cotteswolds the 



