658 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 22, 
or spring tides happened to be in the ascendant. This state of things 
is going on at the present time in the marshes of the Ribble, between 
Preston and Southport, where, after heavy rains or floods, freshwater 
shells may be found, during neap tides, in the hollows in the Scro- 
bicularia-mud, and where, after spring tides, crabs may be found 
living in all the ditches for one or two miles inland. 
In Section 2, and, in fact, in all other sections where the junction 
of the sand dunes with the underlying peat is visible, the base of the 
blown sand is found to be stratified (4!’), and to contain freshwater 
shells, especially Bithinia tentaculata. It would therefore appear 
that when the sand commenced to be blown, both in Cheshire and in 
Lancashire, the surface of the country was a freshwater morass or 
bog, which was gradually filled up by the sand; indeed, in Cheshire 
and at Southshore, near Blackpool (but not, so far as I am aware, 
between Liverpool and Southport, or at Lytham), seams of peat, 
from the tenth of an inch to 3 inches in thickness, occur in the first 
four or five feet of the sand dunes (4”), sometimes as many as ten 
or eleven seams occurring in a foot, always in strictly horizontal 
layers. This stratified sand I have called, for convenience, the 
“ Bithinia-tentaculata sand.” 
West of Section 2, and about 50 yards east of Leasowe Embank- 
ment, the Tellina-sand has thinned out, but reappears on the other 
side of the sea-wall—the two beds of peat, again coalesced, reaching 
a thickness of five feet ; beneath, a thick bed of grey clay occurs, full 
of valves of Scrobieularia piperata. This I have called the ‘“ Lower 
Scrobicularia-clay,” as a bed with Serobicularia lies above the thick 
peat of Lancashire. In this section the first six feet of the sand 
dunes is the “ Bithinia-sand,” with seams of peat, at every 10 or 12 
inches. Above the last seam of peat the sand contains worn marine 
shells, blown in and associated with freshwater and land-shells, 
which lived and died on the spot. 
Still further west, at a point about ten yards north-east of the 
north-east end of the embankment, the peat is about 5 feet thick, 
resting on 9 feet of Scrobicularia-clay, the latter resting on the Upper 
Boulder-clay, which is of a deep purplish red, with blue seams, and, 
under the action of the waves, has been furrowed into long grooves, 
running at right angles, or slightly obliquely to the shore. It is 
honeycombed by marine organisms, and here and there bored by _ 
Pholades. All the pebbles are erratic ; and occasional large boulders 
are seen overgrown with tangle. The surface of the grey Scrobi- 
cularia-clay is, as before, a marshy growth; but it is penetrated by 
the large and massive roots of a perfect forest of trees, found at 
the base of the peat above. 
Further west, in the centre of the embankment, these various beds 
thin very much, the Boulder-clay rising higher, in a kind of boss or 
dome ; and it is therefore probable that the beds above described lie 
in a hollow cut in the Boulder-clay by the Mersey when this tract 
was its estuary. 
Behind the embankment a thin bed of blown sand is found resting 
on peat, near the Leasowe Lighthouse. About 6 feet of this is visible 
