GEOLOGY OF THE BRISTOL COALFIELD. 117 



C?.nal, ^Fr. Smith noticed the fact that tho beds through which 

 the excavation passed were placed in regular sequence, and each 

 possessed its own specific suite of fossils. This fundamental 

 discovery was the keystone of future observations, and after many 

 repetitions in other places, gave rise to the w^ell-known law, — 

 ** That the order of succession of particular strata, with their 

 particular groups of organic remaiiis, ivas never inverted; and that 

 they might he identified at very distant localities hy their charac- 

 ter istic fossils. ^^ From that day to this the fanciful theories of 

 older geologists have been discarded for the present stratigraphical 

 doctrine, and the steady progress in what we believe to be the 

 right direction. 



The whole of the British Isles have been gradually deposited 

 on the eastern slopes of several submarine volcanic rocks, that 

 many ages since protruded into the waters of an ancient ocean 

 that very probably covered the greatest part of the surface of our 

 globe. From the continued action of the waves the deposits on 

 the western side were washed away, while those on the eastern 

 side not being so much exposed to their destructive energy, were 

 more persistent. By successive depositions therefore towards the 

 east was formed that land now so replete, both inside and out, 

 with those sources of wealth that have made our island so famous 

 in the history of the world . 



In order to proceed with system and to avoid confusion, our 

 description will be restricted to that part of the country comprised 

 in our President's accurate and very excellent Map of the 

 ** Bristol Coal-field." It will be found that no other district of 

 similar extent affords so great a facility for obtaining a good 

 knowledge of geology. It extends from Berkeley to Wells, north 

 and south, and westward from Kunney to Huntspill, an area of 

 about seven hundred and twenty square miles, That any 

 member of the society, or visitor to our neighbourhood, may go 

 and study for himself, a complete list of localities and fossils will 

 be given with illustrative sections. 



The foUowins; table of the great divisions of strata that will 



