396 PEOCEEDINGS OF THE GEOLOGICAl SOCrETT. [May 22, 



known to produce grooves on the face of cliffs as well marked as 

 those of glacial times. He had also mentioned the case of a boulder 

 transported by ice which was of such a size as to have occasioned 

 the wreck of a vessel which had struck upon it. 



May 22, 1872. 



John Arthur PhiUips, Esq., of Cressington Park, Aigburth, Liver- 

 pool ; George Fergie, Esq., Conduit Colliery, Brownhills, Walsall ; 

 and Arthur William Lawder, Esq., C.E., Almora, India, were 

 elected Fellows of the Society. 



The following communications were read : — 



1. A Communication from tlie Right Hon. Eaul Geanville, en- 

 dosing a Report from H.M. Minister at Borne relating to the 

 recent Eeupiion of Yesuvitts. 



2. On the Phosphatic Modules of the Cbetaceous Rock of Cambeidge- 

 SHiEE. By the Rev. 0. Fishee, F.G.S. 



(The publication of this paper is deferred.) 



[Abstract.] 



This paper contained an attempt to explain the origin of the 

 phosphatic nodules which lie in a thin bed at the base of the Chalk 

 in Cambridgeshire and are largely extracted, by washing the 

 stratum, for the purpose of making superphosphate of lime. Two 

 hundred and seventy tons per acre, at the rate of fifty shillings a 

 ton, represents the valuable yield of the deposit, which is followed 

 to the depth of about 18 feet. The nodules and other fossils of the 

 bed are chiefly derivative, forming a concentrated accumulation 

 from a deposit belonging to the Lower Cretaceous period. Some of 

 the fossils, however, are believed to be indigenous to the deposit. 

 PKcatulce are attached to all the derivative fossils and nodules ; and 

 the sharp broken surfaces of the latter, with Plicatulce on them, 

 show that they were mineralized before they were deposited in their 

 present gisement. The green grains of chlorite have been drifted 

 into patches. Certain calcareous organisms are preserved ; but many 

 genera of mollusks only occur as casts in phosphate of lime. The 

 deposition of the phosphatic matter has been determined by animal 

 substances. There are two chief varieties of the " ordinary " no- 

 dules. The first are amorphous, or else finger-shaped ; the second 

 formed like a long cake rolled, partially or wholly, upon a stick. The 

 surface of these two kinds of nodules is coriaceous and wrinkled ; 

 and they usually show marks of attachment to some foreign body. 

 Certain species, clearly zoophytes, are converted into phosphatic 



