126 
THE AVONIAN OP THE AVON GOROE 
few feet above the slope where Athyris of. flanosulcata is also 
not uncommon. 
Good rock-specimens of the 82-^ pisolite ’ can be picked up 
from the .debris, and it is not unusual to see in such specimens a 
shell of Seminula surrounded by a concretionary coat half an 
inch thick. 
O2. 
After leaving Quarry 4, the C2-dolomites and shales can be 
recognized, both in the river bank and also by the side of the 
line, but the exposures are unsatisfactory and there is nothing 
to delay us until we reach Quarry 3 (The ‘ Oolite Quarry ’). 
The thick band of Cumma- Oolite forms a striking 
Plate quarry. The well-bedded 
shales and thin limestones capping the thick massive oolite, in 
which the bedding is difficult to recognize, give a momentary 
suggestion of unconformity which is heightened by the vertical 
jointing of the oolite mass, but the impression is immediately 
corrected by the obvious bedding to be seen in the rocks below 
the Oolite, and by the traces of bedding which can be made 
out in the oolite-mass itself. 
The texture of the oolite should be examined under a lens ; 
the oolite grains are usually very much smaller than is the case 
in the oolitic bands at higher levels and the amount of inter- 
stitial cement is relatively less ; the concretionary structure of 
the grains extends almost from surface to centre. 
Fossils are rare in the Oolite but Syringo'pora cf. reticulata 
and Michdinia cf. megastoma occur sparingly. 
The beds below the Oolite form the uppermost portion of the 
laminosa-dio\om\tQ% a division of Ci in which recurrent shell 
seams form a characteristic feature. One of these seams can 
be examined on the bare slopes at the northern end of the 
quarry. 
Orthothetes cf. crenistria and papilionaceous Chonetes occur in 
