AND THE AVON GOEGE. 
17a 
grandeur of its physical features, men, so soon as they began 
to admit the possibility of such features being caused at all, 
searched throughout nature for causes sufficiently potent to 
produce the high ridges, the broad valleys, and the deep ravines 
which they saw around them. One cause alone seemed of 
sufficient power to raise the land into ridges many miles in 
length and a thousand feet or more in height. And that cause 
was fire (so-called), with wffiose work they were well acquainted 
in volcanic outbursts of great magnitude. It seemed, moreover, 
to be obvious that the same volcanic force which upheaved the 
hilly ridge would also tear through its midst huge rents and 
chasms. Speaking, for example, of the Mendips, Dean Buck- 
land said in 1849, in his presidential address at the first annual 
meeting of the Somersetshire Archaeological Society, “ If we 
ask the cause of the extensive elevation of a chain of hills, 20 
miles long, and from 3 to 6 miles wide, and from 200 to more 
than 800 feet in height, we must refer it to the same uplifting 
and explosive force of vapours generated within the earth by the 
subterraneous fires, which are still producing earthquakes and 
exploding ashes and streams of lava in regions which are at 
this time agitated by nearly 200 burning volcanoes on the 
actual surface of the globe. Fractures and dislocations which 
attended the elevation of these strata from the bottom of the 
sea may be seen in the rocks at Cheddar Cliffs, on the east 
flank of Mendip ; and in the yawning chasms of Brockley Combe 
and Goblin Combe, on the west side of Broadfield Down, near 
Bristol ; and in the gorge through which the Avon passes at 
Clifton.” [Proceedings, 1849-50, p. 17.) 
Thus did Dean Buckland, who may be taken as the repre- 
sentative of a bygone age of Geology, account for the upheaval 
of such ridges as we find in our neighbourhood, and at the same 
time for such deep ravines as the Clifton Gorge. And how did 
the Dean account for those wider and more open valleys, in the 
