280 Reports and Proceedings — 



11— April 15, 1885.— Prof. T. G. Bonney, D.Sc, LL.D., F R.S., 

 President, in the Chair. — The following coiuraunications were read : 



1. "A General Section of the Bagshot Strata from Aldershot to 

 Wokingham." By the Rev. A. Irving, B.Sc, B.A., F.G.S. 



The author referred to earlier papers in the Geological Magazine,^ 

 in which the green colouring-matter so common in the Middle and 

 Lower Bagshot strata of the London Basin had been attributed to 

 the presence of vegetable debris and the materials resulting from 

 decomposition of vegetable matter. The marked difference in this 

 respect between these strata and the higher members of the series 

 furnishes a clue to the conditions under which they were respectively 

 deposited, the former being delta- and lagoon-deposits, the latter 

 the deposits of a marine estuary. This implies a transgressive over- 

 lap of the upper portions of the Bagshot series upon the London 

 Clay ; and the present paper was devoted to a consideration of the 

 statigraphical evidence of this overlap. 



Sections were described in detail at x\ldershot, Farnborough, 

 Yateley, Camberley, Wellington College and the neighbourhood, and 

 from the last-named place to Wokingham. From these, a general 

 section was constructed to exact scale, both as to thickness of strata 

 and altitudes, showing a relation of the Bagshot formation to the 

 London Clay, which was inconsistent with the generally received idea 

 of their conformability, and at variance with the mapping of the 

 district as executed by the Geological Survey. 



The importance of the Bagshot pebble-bed as a basement-line of 

 the upper division of the Bagshot strata was shown, as was suggested 

 by the author, so long ago as 1880. 



The synclinal arrangement of the London Clay was shown to have 

 been produced before the deposition of the Bagshot series, though a 

 certain amount of movement (with a resultant amount of 150 feet 

 of tilting in 13 miles from south to north) has since taken place. 



2. " Notes on the Polyzoa and Foraminifera of the Cambridge 

 Greensand." By G. E. Vine, Esq. Communicated by Thomas 

 Jesson, Esq., F.G.S. 



After coiTimenting on the want of published information con- 

 cerning the Polyzoa of the Cambridge Greensand, as shown by the 

 fact that none are mentioned in Mr. Jukes-Browne's list of the fossils 

 (Quart. Journ. Geol. Soc. vol. xxxi. p. 305), the author proceeded to 

 explain the circumstances under which he had been entrusted with 

 the whole of Mr. T. Jesson's collection from the coprollte-bed for 

 description. The collection is large and important, and the Polyzoa 

 contained exhibit a facies distinct from that of the Jurassic beds on 

 the one hand and of the Upper Chalk on the other. There is but 

 little similarity between the collection now described and the forms 

 known from Warminster and Farringdon. The majority of the 

 Cambridge-Greensand Polyzoa occurred unattached to any matrix ; 

 but several examples of attachment have been observed, chiefly to 

 Ostrea, Badiolites, and species of Cidaris. 



A list showing the range of the species described preceded the 

 1 See Geol. Mag. 1883, pp. 404-413, and 1885, pp. 17-25. 



