BRODIE AND BUCKMAN ON THE COTTESWOLD HILLS. 221 



Ammonites heterophyllus Pinna afiinis 



spinatus Spirifer (two new species) 



Stokesi Terebratula tetraedra 



Gryphasa gigantea acuta 



Pecten asquivalvis • bidens 



Cardium truncatum 



3. Upper Lias Shale. A blue argillaceous deposit containing 

 septaria. It is recognised on the hills by exhibiting a line of 

 drainage ; and is traversed by a thin seam of fissile limestone, 

 containing remains of fishes, insects, and shells described lately 

 by one of the authors. The following are the prevailing fossils : — 



Ammonites Strangewaysi Inoceramus dubius 



Walcotti Plicatula spinosa 



annulatus Nucula claviformis. 



4. Inferior Oolite. The lowest bed of the inferior oolite in 

 this district is a pisolitic rock, composed of rounded or flattened 

 grains about the size of peas, cemented by a calcareous paste, and 

 containing fragments of Pentacrinites, &c. Cidaris subangularis 

 and C. coronata, Pecten lens and Avicula contorta, are the chief 

 fossils of this bed. 



A roestone of a yellowish- white colour succeeds this pisolite, 

 and it is found to exhibit numerous small shells on careful exami- 

 nation under the microscope. The average thickness of this bed 

 is J 5 feet ; and the following fossils are found in it, besides the 

 microscopic ones : — Cardita similis, Plagiostoma duplicatum, a 

 JVucula, a Cucullcea (M. C. t. 549. fig. 3.), Patella rugosa, and 

 P. nana. 



Overlying the roestone is a thick bed of white freestone worked 

 in large blocks. This rock is about 25 feet thick, and is a fine- 

 grained oolite intermixed with comminuted fragments of shells. 

 It is overlaid by about 10 feet of oolite marl, resembling chalk, 

 and having an uneven fracture. At Leckhampton and other 

 places it abounds with fossil shells ; but at Crickley and Birdlip, 

 to the S. W. of the Cotteswold, it puts on the character of a coral- 

 line rock. The following list of fossils includes those most 

 characteristic : — 



Astrasa agaricites Astarte elegans 



Madrepora limbata Pinna tetragona 



Agaricia lobata Terebratula fimbria 



Meandrina explanata ? Natica macrostoma 

 Tubipora ? hemispherica 



Plagiostoma laeviusculum Nerinasa fasciata 



A G-ryphite grit, a rough kind of stone, separated from the 

 oolite marl by about 4 feet of flaggy oolite, next succeeds. It 

 abounds with the shells of Gryphcea dilatata in its lower part, 

 and the overlying beds of marl and compact stone are partly com- 

 posed of immense masses of Trigonia costata and T. clavellata. 

 Besides these the rock contains the following species : — 



