THE AVON AND ITS GRAVELS 
229 
west of Wiltshire near Marshfield, which is about four- 
teen miles in a direct line from Avonmouth ; its course 
is over seventy miles long. There is, however, the usual 
local rivalry as to the real source of the Avon ; the 
inhabitants of Didmarton also making out a good case. 
The two results which accompany the action of water- 
denudation and deposition are as usual abundantly evi- 
dent. By denudation the broad and rich valleys have 
been hollowed out, while many accumulations of sand and 
gravel remains as footprints to mark the river’s former 
course. 
The Gravels found in association with the Avon are of 
two kinds : — 
I. An old assemblage of pebbles composed chiefly of 
flint and quartz, found in one spot only, and of doubtful 
origin. These we may call The High Level Gravels. 
II. The more recent deposits found at various heights 
and in different localities along the course of the Avon, 
and obviously due to the action of the present river. These 
may be termed The Low Level Gravels. 
I. The High Level Gravels. 
I. These older gravels occur in a large pocket of the Oolites 
on the escarpment at Kingsdown. In certain conditions 
of the working of the little quarry these pebbles seem to 
be interstratified among the oolitic formation (see fig.). 
At other times the connection with the surface is evident. 
These pebbles were carried into this great cavity and at 
last filled it up. The workings are about 20 feet long, and 
the thickness of the accumulations varies from 5 to 8 
feet. Professor Prestwich thus described the formation in 
1890,^ ‘‘ . . . there is at one spot, Kingsdown, near Bath- 
ford, about 550 feet high and five miles from Bath, a drift 
of the Westleton character. It forms onl}^ a small patch 
on the otherwise bare surface of the Oolites, and consists 
1 Quart. Journ. Geol. Soc., xlvL, p. 143 (1890). 
