778 G. J. HINDE ON SOME FOSSIL CALCISPONGES FROM 
50. On some Fossrt Caxcisponess from the WELL-BoRING at RIcHMOND, 
Surrey. By Grorer Jennuves Hinpe, Ph.D., F.G.8. (Read 
June 25, 1884.) 
[Pirate XXXV.] 
SussE@vENT to bringing before the Society the description of the 
strata penetrated in the Richmond well-boring, Professor Judd 
submitted to me for examination some small fossils of dubious 
character which had been met with in one of the bands of calcareous 
shale intervening between the beds of oolitic limestone at a depth 
of 1205 feet beneath the surface. These fossils were associated 
with remains of Brachiopods, Polyzoa, and other small organisms, 
and presented a similar aspect of fossilization, being throughout 
calcareous in composition. The exterior surface of these bodies 
exhibits a network of delicate fibres with minute interspaces 
resembling that of calcisponges of Zittel’s family Pharetrones. In 
several specimens the basal portion was covered with a delicate, 
more or less wrinkled membrane, and on close observation with a 
strong hand-lens minute three-rayed spicules could be seen here and 
there on the surface ofthis membrane. This fact, at once conclusive 
as to the real Sponge-character of these forms, was further supple- 
mented by the microscopic examination of transparent sections of 
the fibres, in which a spicular structure can be readily detected. In 
all, about 45 examples of these bodies were found in the shale 
examined ; and an idea may be formed of their small dimensions 
from the fact that the entire number can well be contained in a 
tea-spoon. The smallest specimen measures only 2°5 millim. in 
diameter, and the largest 10 millim., or about two fifths of an inch. 
In respect to size they more nearly resemble their existing analogues 
than the Calcisponges hitherto discovered in Jurassic and Cretaceous 
strata ; indeed the relatively larger dimensions of these latter forms 
was brought forward as an argument against their calcareous origin 
by those who regarded them as altered siliceous sponges. But it is 
very probable that if the fossiliferous beds of Jurassic and Cretaceous 
strata were subjected to a similar careful scrutiny to that which has 
been given to the small quantity of material from this well-boring, 
they would be more frequently met with. As a fact, these small 
sponges have so unattractive an appearance that by the majority of 
collectors they would be passed over as small broken-up fragments 
of larger fossils. I do not think, however, that though so much 
smaller than the majority of Jurassic Calcisponges, these forms are 
either immature or imperfect. They show no evidence of having 
been transported to their present position, as the fibres are smooth 
and even, and the dermal layer unworn. 
For the determination of the minute structure thin sections of 
the different forms were prepared; and though in some instances 
only a single example of a species could be spared for this purpose, 
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