EXPLANATION OF THE PLATES. 



Introductory Notice, and Description of the Geological 

 Phenomena illustrated hy Plate 1. 



Plate 1. 



The lower portion of Plate l,is an imaginary section, con- 

 structed to express by the insertion of names and colours, 

 the relative positions of the most important classes both 

 of unstratified and stratified rocks, as far as they have yet 

 been ascertained. 



The merit of this section is due to the talents of Mr. 

 Thomas Webster; it has been enlarged and improved by 

 him from an original section, which he has for several 

 years exhibited in illustration of his lectures ; it was in- 

 tended to illustrate a work on Geology, which he is pre- 

 paring for the press, and he has liberally permitted me to 

 use it likewise in the present work, with some few addi- 

 tions and alterations of my own. 



This Section exhibits under one point of view the rela- 

 tions of the Granitic and Volcanic rocks to the stratified 

 formations, and to one another, more intelligibly than I 

 have ever seen expressed elsewhere. The selection and 

 arrangement of the animals and plants in the upper part of 

 this Plate is exclusively my own ; these have been drawn 

 and engraved (together with a large proportion of the wood- 

 cuts) by Mr. J. Fisher, of St. Clements, Oxford. 



The section is founded on many series of accurate obser- 

 vations, on several lines taken across Europe, between the 

 British islands and the Mediterranean Sea. Although no 

 single straight line exhibits every formation complete in the 



GEOL. II. B 



