128 
THE CRETACEOUS ROCKS OF BRITAIN. 
The plane of division between Nos. 2 and 3 is strongly marked 
the surface of the limestone (2) being phosphatised for a depth of 
18 to 28 man. (Jj to J inch), and in this crust are embedded broken 
phospliatic casts of fossils, while even the small Serpulce on its 
surface are phosphatised. This quartziferous limestone passes 
down into the calcareous sandstone, but the change is rapid, and 
several fossils occur in the upper bed which are absent or rare be¬ 
low, There are 5 or 6 feet of the rough lumpy sandstone, and this 
passes down into hard calcareous sand without lumps, but a layer 
of siliceous concretions is seen on the north side, where about 18 feet 
of hard decalcified sand has been dug. 
The other quarry is on the south side of the road at the western 
end of Wilmington. The face of this quarry is over 30 feet deep, 
but does not show the base of the calcareous sand. In the soil at 
the top are loose lumps of the quartziferous sandstone and large 
blocks of hard calcareous sandstone {grizzle) ; below these are 3 or 4 
feet of soft sandstone, with harder lumpy portions, and in this part 
fossils are very abundant. The rest of the sand contains only a few 
fossils, and it cuts with an even face, being chopped out with the 
broad end of a pick. It is traversed by three layers of siliceous 
concretions, the highest consisting of large flatfish or lenticular 
masses, white or pink outside, and containing a nucleus of brown 
chalcedonic chert. The lower layers are of small irregular concre¬ 
tions. They contain sponge spicules, and seem to be sponges more 
or less filled with sand and cemented by chalcedonic silica. 
Wishing, if possible, to find the base of this sand, I had a hole dug 
in the floor of the quarry, but at a depth of about 12 inches the 
workman reached a hard rocky sandstone, with large sand grains 
and some small pebbles, the whole being indurated and compacted 
by a hard stalagmitic kind of calcic carbonate. The workmen 
stated that a hole had been dug in the orchard outside the pit 
traversing 6 or 7 feet of such rock without reaching its base. The 
total thickness of this calcareous sandstone seems, therefore, to be 
about 40 feet. 
Pebbles also occur occasionally in the mass of the sand. Most 
of them consist of rough vein-quartz, and one in my possession 
measures about lJ x 14 x 1 inches : another is a flat pebble of 
a greenish micaceous sandstone 2-4 inches long. 
List of Fossils from the Zone of Am. Mantelli at 
Wilmington. 
Since the publication of my description of these beds I have 
obtained a large number of fossils from the workmen who dig the 
sand from the pit south of the village, and am now able to give a 
much longer list of species. A few of them appear to have come 
from the remnants of the quartziferous limestone left in the soil, 
