EXPLANATION OF PLATE I. 3 



As it would encumber the section to express Diluvium, 

 wherever it is present, it is introduced in one place only, 

 which shows its age to be more recent than the newest of 

 the Tertiary strata; it is found also lodged indiscriminately 

 upon the surface of rocks of every formation. 



Granite. 



In our early Chapters we have considered the Theory 

 which refers unstratified rocks to an igneous Origin, to be 

 that which is most consistent with all the known Pheno- 

 mena of Geology, and the facts represented in the Section 

 now before us are more consistent with the Postulates of 

 this Hypothesis, than with those of any other that has 

 hitherto been proposed. I have, therefore, felt it indispen- 

 sable to adopt its language, as affording the only terms by 

 which the facts under consideration can be adequately de- 

 scribed. 



Assuming that Fire and Water have been the two great 

 Agents employed in reducing the surface of the globe to its 

 actual condition, we see, in repeated operations of these 

 agents, causes adequate to the production of those irregular 

 Elevations and Depressions of the fundamental Rocks of the 

 Granitic series, which are delineated in the lower Region of 

 our Section, as forming the basis of the entire Superstructure 

 of stratified Rocks. 



Near the right extremity of this Section, the undulating 

 surface of the fundamental Granite (a. 5. a. 6. a. 7. a. 8.) is 

 represented as being, for the most part, beneath the level of 

 the Sea. 



On the left extremity of the Section (a. 1. a. 2. a. 3.) the 

 Granite is elevated into one of those lofty Alpine ridges, 

 which have affected, by their upward movement, the entire 

 series of stratified Rocks. 



Corresponding formations of Primary and Transition 



