LOWER CHALK—MICROGRAPHIC STRUCTURE. 
305 
Sponge-spicules are to be seen only in two or three specimens. 
In one from Furley, near Membury, there occur the same forms 
already alluded to in the Chalk Marl as possibly those of Radiolaria. 
Isle of Wight.— Along the south coast specimens present the 
same peculiarities as those of the inland localities. The basal 
beds of the Isle of Wight contain a large proportion of shell-fragments 
and much glauconite, thus faintly echoing, as it were, the conditions 
of the Totternlioe Stone. In the higher parts amorphous calcareous 
matter predominates, shelly fragments occur sparingly, while 
“ spheres ” are scattered through the mass, with minute Globigerm a 
and Textularia. 
Kent , Dover. — The specimen from 70 feet below the Belemnite 
Marl (36) contains about 10 per cent, of finely divided shell-frag¬ 
ments and 10 per cent, more of “ spheres ” and minute Globigerina 
and Textularia and foraminiferal cells, the greater part of the 
rock being amorphous material, chiefly calcareous, but containing 
fine inorganic matter also. At 40 feet below this Marl the chalk 
is nearly all amorphous material with very few shell-fragments 
or “ spheres,” though the minute Foraminifera noted above are 
still in evidence. The sample from 6 feet below the Belemnite Marl 
(37) is very similar, containing even fewer foraminifera “ spheres ” 
or shell-fragments. 
Wiltshire.—We have but few specimens from this zone from 
Wilts. One each from Scratchbury Hill, Arn Hill, and Clay Hill, 
all near Warminster, are evidently from nearly the same horizon, 
probably about that of the Totternlioe Stone, or at least the base 
of the zone. . Shell-fragments and “ spheres ” are abundant, the 
former somewhat coarse, these, together with a few Foraminifera, 
forming about 50 per cent, of the deposit. Comparatively large 
grains of glauconite are common, and the mineral grains are larger 
and more abundant than in other specimens of chalk at a similar 
horizon except that from South Dorset. In two specimens from 
the upper part of the zone from Brimsdown, near Devizes, 30 feet 
and 15 feet below the Belemnite Marls the rock is chiefly amorphous 
material, with but few shell-fragments or “ spheres/' the latter 
being most abundant in the highest example. In both small mineral 
grains occur with a few of glauconite. This is the highest horizon 
at which mineral grains have been recognised in a section. As in 
Dorset, Foraminifera are not common. 
Berkshire and Oxfordshire.—J udging from specimens from 
various horizons in this zone in Berkshire, the general appearance 
of the Chalk does not alter much. In the lower part of the zone it 
is shelly and full of “ spheres,” but it passes up to a rock consisting 
chiefly of amorphous matter. Both mineral grains and glauconite 
occur, and the former are more abundant than in chalk of the 
same horizon to the northward. 
We have a good series from Crowmarsh (Oxfordshire). Im¬ 
mediately above the Totternlioe Stone the chalk resembles that 
