24 
HOLDERNESS. 
scotica, but is certainly of a different genus. The shells are most abun- 
dant along particular layers in the gravel. The mass descends to a great 
depth, and is found beneath the adjacent marshland, which consists of 
fine clay, lying upon peat and trees, and is part of an extended level 
tract, reaching from the Humber near Pattrington, almost to the sea, at 
Sandley mere. It seems to have been, at some former period, a chan- 
nel for some vast volume of water ; for it winds as other vallies do, 
and the gravel hills which bound it are abrupt on the concave side, 
and slope gently down on the other. 
In the cliffs against the Humber at Paul, very similar phenomena 
are observed. The gravel and sand are here remarkably contorted, and 
intermixed with alternating layers of a sediment much like warp. The 
shells are of the same kinds as in the pit near Ridgemont, in similar 
disorder, and equally plentiful. The pebbles and fossils, mixed with 
them, are also very similar, but the masses are generally very small, and 
flint is more abundant, a circumstance probably depending on the proxi- 
mity of the chalk wolds. 
As these are the only examples of recent marine shells mixed with 
diluvial detritus which have fallen under my examination, I hardly 
presume to offer any conjectures as to the peculiar conditions of the 
waters which heaped them together. Repeated investigations of the 
tracts over which fragmented rocks were dispersed from their original 
sites, have convinced me that many local eddies and minor currents 
interfered with the great diluvial streams, and often caused an accu- 
mulation in one spot, of materials brought in very different directions. 
Such an explanation may, I imagine, be applied to the case before us ; 
but until analogous examples shall be adduced, and the history of the 
crag stratum of Norfolk and Suffolk be more adequately developed, the 
subject must remain in obscurity.* 
* Very interesting and somewhat analogous cases have been since observed by Mr. W. Gilbert- 
son, in the vicinity of Preston, and by Mr. Trimmer on the slope of Snowdon. 
