THE EAR AND HEARING. 
281 
strewn on the ground; also a small quarry may be seen, 
exposing a section of three or four feet ; it is very similar to 
that at the base of the hill. Here, and at other places around 
Chalcomb, the Middle Lias rock-bed seems to follow the 
undulations of the ground, and is met at such different levels 
as to suggest that the hills are due to elevation and not to 
denudation as in most other places in the county. 
In and around Chalcomb there are several sections of the 
Marl stone; one by the side of the Thorpe Mandeville road 
shows a small fault ; the light-coloured clay of the lower 
part of the Upper Lias being brought, for a short distance, 
side by side with the rock-bed. Another section in the village 
exposes about five feet of a rather soft rubbly stone, contain¬ 
ing many fossils of the common kind, also calcspar. On a 
hill to the south-east of Chalcomb there are two or three 
small quarries, and a year or two ago one in the middle of a 
cornfield was being worked for road metal. In the district 
around Chalcomb there is no clay capping to the rock-bed, 
hence the stone is very much fissured and broken, and fit for 
little besides road mending ; it has, however, furnished a 
rich red soil, very well suited to wet seasons because of the 
very good natural drainage it allows. On making enquiries 
I was informed that this district suffered very little from the 
heavy unseasonable rains of a few years back. 
I believe there are no exposed sections of the Marl stone 
north of Chalcomb until we reach Edgcott, a distance of 
about 2b miles. Near to Edgcott Church we find a small 
quarry that is occasionally worked for road material. The 
soil above it contains broken pieces of limestone, with 
Ammonites serymtinus, A. communis, dec., which are evidently 
the remains of the Lower Cephalopoda bed. Some very 
fine specimens of RhynchoneUa tetrahedra were obtained from 
the heaps of stone near at hand. 
(To be continued.) 
THE EAR AND HEARING 
BY W. J. ABEL, B.A., F.R.M.S. 
(Continued from 217.) 
It. Pitch, supposed to be discriminated by the responsive 
vibration of the rods of Corti, signifies the acuteness or 
graveness of the sound as determined by the ear ; and is 
resolvable into the rate of vibration of the sounding body. 
