16 CHELTENHAM COLLEGE NATURAL HISTORY SOCIETY. 
GEOLOGICAL SECTION. 
HE First Meetinc was held on Feb. 14th, when 
Mr. Wethered gave an address on Microscopic 
Geology. Magnificent slides, photographs of 
microscopical sections, were used to illustrate the 
: lecture. Several views of rocks in the neighbour- 
hood of Clifton were first shewn ; some of the rocks in the gorge of 
the Avon being 300 feet high. These rocks are all made up of the 
remains of minute animals, which when dead fell to the bottom of 
the sea and the skeletons slowly and steadily produced the masses 
of rocks tuwering up above the bed of the river. 
Then the great Black Rock was shewn, a cliff nearly 400 feet 
in height mostly made up of the little disks of Encrinites with a hole 
in the centre of each. These are the remains of skeletons 
which consisted of about 26000 joints, and they must have existed 
in enormous numbers to pile up such great masses of rock composed 
entirely of their remains. The joints consist of Carbonate of Lime 
which sank when the animals died. The Sea Anemone has no hard 
part or skeleton, consisting as it does of a soft fleshy body. The 
Coral has a skeleton of Carbonate of Lime which branches out in 
various directions, and if a bit gets broken off it grows to form fresh 
coral polypes. There is an ancient coral reef at Horsepool beyond 
Gloucester, and another at Clifton. 
The small things known as Foraminifera are masses of living 
matter without any definite structure, but only oil globules encased 
in Carbonate of Lime. This is pierced with small holes, each of 
which sends out a kind of proboscis, which form a net and catch 
smaller organisms. The Cathedral Rocks at Cheddar are made up 
of the shells of Foraminifera. 
The Oolite is composed of a nucleus with layers which have 
formed round it. This nucleus is either a minute shell or a grain 
of sand round which the Carbonate of Lime has collected. The 
Pea Grit consists of animal tubes grown round and round the 
central nucleus. 
