PROCEEDINGS OF GEOLOGICAL SOCIETIES. 



297 



although Dr. Wright had proposed the following classification — 5. Ammo- 

 nites Bucklandi zone ; 6. A. Planorbis zone (including the White Lias and 

 the Ostrea beds) ; and 7. Avicula contorta zone, yet he preferred to group 

 them thus — 5. A. Bucklandi zone; 6. A. Planorbis zone; 7. Enaliosaurian 

 zOne ; 8. White Lias ; 9. Avicula 'contorta zone : 8 and 9 being equivalent to 

 the " Kossener Schichten" or "Rhsetic beds" of Giimbel and other Conti- 

 nental geologists. 



The arguments in favour of his views the author based chiefly on ob- 

 servations made at Beer-Crowcombe, Stoke St. Mary, Pibsbury, Long Sutton, 

 and other places in Somersetshire ; and on a critical examination of the sections 

 at Street, Saltford, &c. as given by Dr. Wright. 



The communication concluded with descriptions of upwards of sixty species 

 of fossils belonging to the Rhsetic beds of England (including their thin re- 

 presentatives discovered by the author in the Vallis near Frome) ; twenty-eight 

 of these species are new. 



June 5, 1861. 



1. "On the Occurrence of some large Granite Boulders, at a great depth, in 

 West Rosewarne Mine. Gwinear, Cornwall." By H. C. Salmon, Esq., F.G.S. 



The boulders of granite referred to were found in the 50-fathom level below 

 the adit, the adit being 21 fathoms from the surface. One of the boulders 

 was 4 feet 2 inches, and another 3 feet 10 inches in diameter ; there were five 

 other smaller boulders or pebbles also met with in the level. The boulders are 

 in the killas close to the lode, and both the lode and the " country" near the 

 lode are made up of brecciated killas. After quoting the details of somewhat 

 similar phenomena formerly observed at Relistian and Herland Mines, the 

 author treated of the probable origin of the boulders in question ; and al- 

 though lodes are regarded by some as having been formed from below upwards, 

 yet in this case the author thinks that the boulders must have had a common 

 origin with the lode, and have been introduced by a fissure from the surface. 



2. "On an erect Sigillaria from the South Joggins, Nova Scotia." By Dr. 

 J. W. Dawson, E.G.S. 



This specimen, presenting the external markings of leaf-scars and ribs with 

 more than usual clearness and with some instructive peculiarities, has afforded 

 to the author the type of a new species, Sigillaria Broionii. Observations on 

 the probable style of growth, on the structure, and on the classification of 

 Sig i lia r ice, were also given in this paper, together with a resume of the obser- 

 vations previously published regarding Sigillaria by Brongniart, Corda, and 

 others. 



3. "On a Carpolite from the Coal-formation of Cape Breton." By Dr. 

 J. W. Dawson, F.G.S. 



Numerous Trigonocarpa belonging to a new species {Trigonocarpum Hookeri) 

 occur in a thin calcareous layer in the coal-measures near Port Hood, Cape 

 Breton. The author thinks it highly probable that, though some Trigonocarpa 

 may have belonged to Conifers, yet in this case they were the seeds of Sigil- 

 laria. 



4. " On a Reconstructed Bed on the top of the Chalk." By W. Whitaker, 

 Esq, B.A, F.G.S. 



At some places near Reading (Maidenhatch Farm, about six miles to the W. ; 

 and Tilehurst, two miles to the S.W.), and also near Maidenhead, from 18 to 

 twenty feet of broken chalk overlies the true chalk ; and in places is overlain 

 by the bottom-bed of the Reading Beds, and therefore must have been recon- 

 structed before the deposition of the Tertiary strata. For the most part, how- 

 ever, in Berkshire the Woolwich and Reading beds rest on an undisturbed sur- 

 face of the Chalk. In Wiltshire, also, the author has observed similarly con- 

 structed chalk, probably there also underlying Tertiary beds ; and he suggests 



VOL. IV. 2 H 



