KIMMERIDGE CLAY FOSSILS : FENSHUKST. 197

to Dr. P. A. Bather, who has recognised them to be the radial
plates of Saccocoma, and has furnished us with a short pre-
liminary account of them 1 . These minute, thin, scutiform,
plates were only found at depths between 1,794 feet and 1,807 feet.
They are all pyritized, and are the only organisms observed to be
fossilised in this manner in this part of the clays. They occurred
abundantly on several layers between these depths, but were not
found in any other of the borings, nor could we discover anything
resembling them in the public collections of Kimmeridge fossils.
It curiously happened, however, that one of us [G. W. L.], shortly
after finding the form at Penshurst, chanced upon further
examples in a large transported fragment of shale embedded in
the Ferruginous Sands of the Lower Greensand at Little Stairs
Point, near Sandown, in the Isle of Wight 2 . The new occur-
rence was doubly interesting in proving (1) that the Kimmeridge
Clay was exposed to erosion at some neighbouring place in Aptian
times ; and (2) that the little fossil is likely to have been widely
distributed. Attention having now been drawn to it, we may
expect that it will be discovered in the Kimmeridge Clay at other
localities.
1 'Summary of Progress' for 1910 (Mem. Geol. Surv.), 1911, Appendix II,
p. 78.
2 This occurrence was mentioned in ' Summary of Progress ' for 1900 (Mem.
Geol. Surv.), 1901, pp. 118, 119.
198



CHAPTER XIII.
PAL^EONTOLOGICAL SUMMARY.
The correlation of the marine Jurassic strata passed through
in the four sections is represented diagrammatically in Plate V.
