PLATE VIII. 
Fig. 1. 
Base of the Terebratulina zone, Hitchin, Herts. 
This figure shows a structure very characteristic of the chalk in the 
upper part of the zone of Rhynchonella Cuvieri , and the base of the 
Terebratulina zone. 
“ Spheres ” are very numerous. These usually show a cell wall with 
the interior filled with granular calcite, a. a.; or the wall may be 
obliterated, b; c. Globigerina cretacea ; d. Globigerina marginata. 
Fig. 2. 
Upper Chalk zone of Belemnitella quadrata, Salisbury, Wilts. 
A soft chalk consisting chiefly of amorphous material with a few 
shell fragments and minute foraminifera, chiefly Globigerinae. and 
Textularians. Amongst the latter are many T. globulosa , a character¬ 
istic form in many sections of Upper Chalk. 
a.a.a.a. Textularia globulosa ; b. Globigerina oequilateralis ; c. Foram- 
iniferal cell. 
