88 
RED CRAG. 
and in them on the north. A few feet greater depth would reach 
the London Clay. I class the whole of the sand of this well- 
known section with the Crag, there being no real division in it, 
the absence of shells being due clearly to nothing but dissolution 
after deposit. The top part is inaccessible.” 
According to Mr. Wood the Crag of Bentley, though decidedly 
newer, is more closely allied to that of Walton than is any other 
part of the Eed Crag; the northern shells so conspicuous else¬ 
where are scarce here.* 
In the adjoining valley of Tattingstone, Mr. Whitaker notes 
that some sections showed clearly the relation of the ferruginous 
beds to the shelly Crag. He observes that a Crag-pit nearly 
half a mile north-north-west of Tattingstone Church, on the 
southern side of and close to the farm, showed more than 20 feet 
of Red Crag (with some small faults), consisting of false-bedded 
sand, passing down irregularly into false-bedded shelly Crag. 
There were marly phosphatic nodules in certain layers, and lenti¬ 
cular masses of ironstone and ferruginous'loam, chiefly without 
shells. The shelly Crag was very rich in PectunculuSy and with a 
tendency to layers of Fusus contrarius. Some of the lower part 
was made up of broken-up shells.” 
A small pit on the eastern side of the little valley, eastward of 
the farm named Bentley Lodge, gave the most conclusive proof 
of the dissolution of the shells of the Crag by infiltration of car¬ 
bonated water having been the cause of the irregular junction of 
the shell-less brown sand with the ordinary shelly Crag, the section 
being as follows:—Very coarse dark brown sand, almost all a grit 
indeed ; with a gravelly layer, 1 to 2 feet thick, above the middle, 
containing phosphatic nodules and ferruginous casts of shells, the 
stones small and scattered. Just under the gravelly layer a 
little iron-sandstone, with casts of shells, below which the sand is 
false-bedded and passes down into the shelly Crag, the line between 
being clearly one of dissolution of the shells and not of erosion, as 
it cuts across the beds, to a lower level towards the stream. Near 
the bottom is a second bed, 1 to 1^ feet thick, of small scattered 
pebbles and phosphatic nodules, with iron-sandstone, and, more¬ 
over, with shells or casts of shells, according to the position of the 
bed with regard to the line of dissolution, the bed being at one 
part in the shell-less, and at another in the shelly sand.”| 
In the pit at Park Farm, Tattingstone, we meet with clear 
evidence of the erosion which the Coralline Crag underwent pre¬ 
vious to the deposition of the Red Crag. The section is now 
obscure, but Prof. Prestwich has published J a sketch of it as 
formerly seen ; this, with his consent and by permission of the 
Council of the Geological Society, is here reproduced :— 
* Supplement to the Monograph of the Crag Mollusca, Introduction, p. vii. 
PalcBontographical Society. (1872); and note to Synoptical List at end of 
Supplement, p. 203. (1874.) 
f Geology of Ipswich, p. 47. 
I Quart. Journ. Geol. Soc., vol. xxvii., p. 342. (1871.) 
