INTRODUCTION. 
XIX 
conclusions, drawn chiefly from examining the interior of the district, 
were consonant to those of my distinguished friend derived chiefly 
from the western border. 
A valuable contribution to the philosophy of geology, by Mr. Hop- 
kins, has just been printed for the Cambridge Transactions, and it is with 
extreme gratification that I find the deductions from mechanical prin- 
ciples , as to the direction and other circumstances of the fissures and 
displacements of rocks, contained in this interesting Essay, perfectly in 
accordance with the inferences or laws of phenomena to which observa-r 
tion had conducted me. Had Mr. Hopkins’s demonstrations in Geologi- 
cal Dynamics, been known to me before the Chapter on Subterranean 
Movements, (p. 99, & c.) was printed, my views could not have been 
adduced, as it appears to me they ought now to be, in confirmation 
of his very important conclusions. The remarkable result arrived at by 
the tabulation of my observations on the Symmetrical Structure of 
Rocks, (Chap. iii. p. 90.) of two positive and two negative axes of 
fissure, the axes of each pair respectively perpendicular to one another, 
was totally unexpected when the table was composed, and no other 
observations or investigations for the same object being published, pru- 
dence suppressed speculation ; but I do not think the causes of the 
symmetry represented in the Diagram p. 98, beyond the scope of Mr, 
Hopkins’s researches. 
The excellent work of The Messrs. Sowerby, entitled the Mineral Con- 
cliology of Great Britain ; Martin’s Petrificata Derbiensia ; Parkinson’s 
Organic Remains ; Miller’s and Cumberland’s works on the Crinoidea ; 
Hr. Ure’s Rutherglen ; and some figures of Orthoceratites communicated 
to the Annals of Philosophy by Dr. Fleming ; contain nearly all the 
graphical representations of mountain limestone fossils accessible to the 
English reader. 
It was important to supply this deficiency, by a large series of 
characteristic figures ; and it is with a sense of real obligation that 
I mention the name of Mr, Lowry, who, in engraving from my draw. 
