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VII. On Beds of Sponge-remains in the Lower and Upper Greensand of the South of 
England. 
By George Jennings Hinde, Ph.D., F.G.S. 
Communicated by Henry Woodward, LL.D ., F.R.S., F.G.S. 
Received April 29.—Read May 21, 1885. 
[Plates 40-45.] 
In the course of a search for fossil sponges in the lower cretaceous deposits of the 
South of England, I have noticed the occurrence at different horizons of beds of rock, 
of not inconsiderable thickness, composed to a large extent of the spicular remains of 
sponges. The strata in which these remains occur are well known, and they have 
been described in numerous papers from the date of Dr. Fitton’s celebrated memoir of 
“ The Strata between the Chalk and Oxford Oolite,” in 1827, to the present time, but 
owing probably to the microscopic dimensions of the remains, and the various changes 
in their fossilisation which have oftentimes rendered them unrecognisable to ordinary 
observation, the # organic character of the strata has been seldom recognised, and only 
in one or two cases have their contents been noticed in detail. The beds have 
usually been regarded as deposits of sandstone, chert, or siliceo-calcareous materials of 
an inorganic nature; but though in most cases they contain a varying amount of 
mechanically derived materials, yet the sponge-remains, and the siliceous deposits 
derived from their solution, constitute such an important part of their volume as to 
entitle the beds to be classed as of organic origin, in the same sense as, for example, 
the upper chalk of this country. In nearly all the outcrops of the lower and upper 
greensand of the south and south-west of England these sponge-beds are exposed, 
differing, however, considerably in their development, in the nature of the sponge- 
remains, and in their condition of fossilisation in different areas, and it is my purpose 
m this paper to treat (I.), of the general characters of the beds in the various localities ; 
(II.), of the mineral condition of the sponge-remains and of the beds derived from 
them; and (III.), of the nature of the sponges present in the deposits. 
I may premise that the sponge-beds to be referred to, do not, with one or two 
exceptions, consist of the skeletons of these organisms in a complete or partially 
complete condition ; but they are made up of innumerable multitudes of the detached, 
minute, microscopic spicules of which the skeletons are composed. The deposits 
appear to have been produced by the disintegration of the skeletons of numerous 
generations of sponges, which have successively lived and died in the same areas in 
* Mr. J. Arthur Phillips mentions the presence of numerous fossils, particularly sponge-spicules, 
in cherts of lower greensand age. “ On the Constitution and History of Grits and Sandstones,” Quart. 
Journ. Geol. Soc., vol. xxxvii., 1881, p. 16. 
