Lower chalk— kiciioGlurmc structure. 30? 
in the upper part of the zone is the increase in the number of Globi- 
gerina and Textularia. Both are usually very small, and the 
relative number seen in each example varies, but they are decidedly 
more numerous as a whole than in the more western samples. 
Cambridgeshire.—At Cherry Hinton the following sequence of 
examples was obtained, and may be compared as showing the 
general aspect of samples of this zone in the Midland counties, taken 
at measured distances below the Belemnite Marl. 
80 feet.—“ Spheres ” estimated at 60 per cent.; shell-fragments 
not common ; Foraminifera rare; one or tw T o glauconitic 
grains; no minerals observed. 
60 feet.—Fine shelly fragments, “spheres,” and Foraminifera 
do not form more than 15 per cent, of the deposit; Globi¬ 
gerince present, mostly of minute size, but two or three 
larger ones. 
45 feet.—" Spheres ” about 20 per cent.; shell-fragments rare; 
no Foraminifera, glauconite, or quartz. 
30 feet.—Almost entirely amorphous material ; neither 
“ spheres ”■ nor shell-fragments ; a few minute Forami¬ 
nifera ( Globigerina or Textularia.) 
15 feet.—" Spheres ” fairly common; a few shell-fragments, 
and minute Foraminifera; amorphous material 85 to 90 
per cent. 
6 feet. —Shell-fragments coarse, abundant; "spheres” com¬ 
mon ; many minute Globigerina and Textularia; a few 
large specimens of the first named genus; the recognis¬ 
able ingredients forming about 35 per cent, of the rock. 
Norfolk and Suffolk.— The conditions indicated by the Cherry 
Hinton series continue through these counties, but as one progresses 
towards North-west Norfolk there is a general increase of shell 
fragments, and large Globigerince become a more constant feature, 
though the chalk still consists largely of amorphous matter. 
Lincolnshire.— Through this county the chalk contains a large 
proportion of coarse particles which can be recognised as shell, 
while in some specimens " spheres ” and Foraminifera are fairly 
numerous. Examples from the quarries near Louth contain from 
5 to 10 per cent, of shell-fragments; " spheres ” are common, and 
these, with small Textularia, small and large Globigerince , and 
here and there a Rotalina , together make up from 10 to 15 
per cent, more of the rock. 
There seems to be no important difference in the structure of 
the pink bands which occur in the zone. 
Y orkshire.— Throughout Yorkshire the character of the chalk 
continues much the same, though some examples contain a still 
larger percentage of shell-fragments and Foraminifera. For in¬ 
stance, a specimen of the pink band at Swinham contains at least 
50 per cent, of recognisable shell-fragments and Foraminifera, 
4219. X 
