Essay on Geology. 97 



and these formations constitute the whole of the geological series, except- 

 ing mica slate and gneiss, among the primitive rocks ; (granite, as we have 

 said, does shew itself in the Quantocs ;) and England presents us with no 

 decided examples of what is here wanting, the nearest point where we can 

 examine them being the Scotch Grampians. At the other extremity of the 

 series, we do not indeed find the tertiary formations within our circle 3 for 

 these we must go to the coasts of Hampshire and the Isle of Wight. Al- 

 though there is another important class of rocks we have not yet noticed, 

 namely, the intruded masses of trap rock, of supposed igneous origin, yet 

 dykes of this description occur within our thirty miles circle, at Tortworth, 

 beyond the northern border of our coal field ; they there traverse the old 

 red sandstone, and subjacent transition limestone, which there emerges. 

 Their phsenomena may therefore also be studied within our field : and this 

 particular locality most strongly illustrates the multum in parvo which 

 generally characterises our district, as we have here these intrusive rocks, 

 and the whole series of regular formations, from transition limestone, to 

 the oolites of Wotton-Uuder-Edge inclusive, brought within the astonish- 

 ingly narrow compass of about three miles. 



Wq have thus endeavoured, from our most commanding station, to point 

 out to our readers the very wide and interesting field of geological research, 

 spread before their feet, and continually inviting their examination j and 

 this, as we have said, must be ever by far the most efficient, as well as the 

 most interesting and delightful, school of Geology. Still we must not 

 forget, that the alphabet of our science, the knowledge which will enable a 

 person to tell one species of minerals and organic remains from another, 

 must first have been acquired elsewhere, (in cabinets and museums) before 

 our observer can be adequately prepared to profit by his actual examination 

 of nature ; and that examination will be rendered doubly profitable, if he 

 has the opportunity of consulting, from time to time, copious and well- 

 arranged collections, and comparing with them the specimens he may him- 

 self have succeeded in procuring. Now we believe we may boldly say, that 

 no other provincial institution is at this moment so richly furnished, as that 

 of Bristol; and we know that one of the most active and intelligent conti- 

 nental naturalists of the day, M. Agassiz, warmly expressed himself to the 

 same effect, when he visited Bristol, towards the close of a very extensive tour 

 of inspection, through most of the towns in our island, which possess such 

 institutions, for the purpose of availing himself of any resources which they 

 might offer to assist him in the prosecution of his great work, the History 

 of Fossil Ichthyology. We shall briefly, therefore, state the general nature 

 and extent of our collections bearing on the present subject : and it is one 

 of the points in which we flatter ourselves that our efforts may render the 

 most essential benefits to the interests of science in Bristol, if by statements, 

 like that on which we arc now about to enter, we shall succeed in ren- 



No. 2.— Vol, r. o 



