296 THE MEDALS OF CREATION. Cuap. VIL. 
A lobed zoophyte, resembling the above in its general 
form, and long rootlets, is distinguished by a large central 
cavity, which is continued above the body in the form of a — 
cylinder.* 
Sponeites (?) FLExuosus. Lign. 80, fig. 10.—Among the 
cyathiform flints that abound in the chalk, a very elegant — 
species is distinguished by a flexuous band that runs round 
the margin, and indicates the lobed structure of the original. 
In the chalk of Flamborough Head, Yorkshire, many — 
beautiful cyathiform sponges are preserved, in which the — 
outer surface is thickly covered with projecting hollow pa- — 
pill ; these fossils are generally silicified, the surface and 
pores being frosted over with minute quartz crystals. The 
museum of the York Institution contains a splendid series — 
of these spongites.+ 
Fossiz ZoopHytes oF Fartnapon. Lign. 70, 71, 72.— — 
The richest locality for fossil sponges in England is in the 
immediate neighbourhood of the little town of Faringdon, — 
in Berkshire~. The Greensand beds that overlie the Oolite — 
in that district, consist of a coarse friable aggregation of 
sand, comminuted shells, corals, amorphozoa, and echino-— 
derms, more or less consolidated by a ferruginous cement. | 
The gravel-pits, as the quarries are locally termed, expose — 
what evidently were banks of detritus thrown up on the 
strand of a sea-margin ; among the waterworn and fragmen- 
tary relics of oolitic as well as cretaceous forms, many perfect — 
* Beautiful figures of these and other chalk zoophytes are given by — 
Mr. Toulmin Smith in his elegant memoir “On the Ventriculide.” — 
The specimens above described are named Brachiolites by Mr. Smith. 
The plan of the present work forbids the discussion of that author’s — 
opinions and inferences. q 
+ The silicified state of these zoophytes was first detected by Mr. © 
Charlesworth, who by immersing specimens in dilute hydrochloric — 
acid, obtained admirable examples of the delicate structure of the — 
original. 
+ See Excursions, in vol. ii. i: 
