450 
THE GEOLOGIST. 
conglomerate on the Maidstone hills, near the sites of the ' grey- 
wethers.' " 
The statement of the late Dr. Mantell still holds good, that "no 
regular stratum of the ' Druid sandstone ' has yet been discovered 
in this country, and its geological position is still undetermined." 
Preston Quarry, on the south side of 
the Medway, ofters a fine section of the 
effects of an elevating force, as may be 
seen in the accompanying sketch (fig. 
11). The stone is fractured in all di- 
rections, and consequently large blocks 
are not obtainable. The diagram, fig. 12, 
^. . .. 1- 1 i T. i. gives the continuation of the disturbed 
Fig. 11. — Anticlinal at Preston ^ , ^ 
QuaiTV. « ^r, black greys ; b b, ^ • ^ ^- ^ n 
molluskite bed; c c, loamy clay The most interesting part of 
and greensand, with beds of stone quarry is the bed of loamy clay, c c. 
bored with lithodomi at c' ; d, ig about three feet in thickness, 
surface falling to the Medway. contains fragments of shells— oysters, 
terebratulae, corals, etc. In detached pieces, with their edges rounded, 
is a layer of stones, varying in thickness of about 2 inches by 6 or 
the 
It 
and 
Preston Quarry. 
Medway. 
Fig. 12. Section of Preston District. 
12 inches across. Their upper surfaces {c' c') are perforated by litho- 
domi, and the perforations are tilled with the loam and a white pow- 
dery deposit. The excavations are about 2 inches in depth ; and one 
fragment is so perforated, that not a square inch of it remains intact. 
COEKESPOXDENCE. 
Origin of Flint in Chalk. 
Dear Sie, — Elint in chalk is found as bands of nodules or thin seams 
separated from each other by intervals of chalk varying from a few feet to 
many yards ; the nodules, from a boy's marble to two or three feet in 
diameter. In some pits only solitary flints occur here and there ; in others, 
in tlie same upper flint-bearing chalk, there are no flints at all. 
We have terebratulae composed of pure flint extracted from blocks of 
equally pure chalk. 
I consider it very doubtful whether the flints have been deposited suc- 
cessively with the beds of chalk. Flint nodules, it appears to me, are 
actually in process of increase at this day. Yours truly, 
EOBT. MOETIMEB. 
Fimher, Malton, November IZtJi, 1862. 
