THE GEOLOGIST. 
OCTOBER, 1860. 
GEOLOGICAL L 0 C A L I T I E S.— No. L 
FOLKESTONE. 
By S. J. Mackie, F.G.S., F.S.A. 
(Continued from page S27.) 
Of all tlie Gaiilt fossils, the Ammonites take precedence botli for 
bsauty and number; and, holding as the Cephalopods do the highest 
rank of molluscous animals, we cannot but view their extraordinary- 
variety in this deposit with singular interest. If, therefore, we dwell 
here somewhat at length on theu* general classification, we could 
scarcely choose a more fitting occasion. 
As ordinarily seen in collections, the Gault Ammonites appear to 
be all more or less of diminutive size. Few exceed two inches in 
diameter ; many are little more than an inch ; while one of three 
inches would be looked upon as a fine individual. 
These specimens are, however, for the most part only the central 
whirls solidified or hardened by interior walls, or in-fillings of iron- 
pyi'ites. In the Gault itself Ammonite-shells of far larger size — 
commonly of six or seven inches across, sometimes more than a foot 
■ — are not merely frequent, but extremely abundant, although, from 
the fi'agile state of the main mass, they are commonly cleft to 
pieces in breaking out the central pyritons cores without attracting 
obsei*vation. 
Even if collected, theu* tendency to peel away fi-om the matrix 
VOL. III. 2 Y 
