4% 
Geological Society of London. 85 
Phillips has described the physical geography of the district occu- 
pied by these rocks, their lithological character, stratification, jointed 
structure, and the most remarkable faults which affect them, espe- 
cially those which have been called the great Penine and Craven 
faults. He also treats of the trap dykes which cut through the 
limestone, and discusses the probable epochs of the displacement of 
the strata, judiciously pointing out the difficulties unavoidably op- 
posed to the rigorous determination of the date of such dislocations. 
A large and very valuable portion of the work is filled with deserip- 
tions and plates of organic remains, especially of the brachiopodous 
and cephalopodous mollusca. Most of the species of these classes 
were probably inhabitants of the deeper parts of the sea, but there 
are fossil shells in the mountain limestone, which the author sup- 
poses to have lived near the shore, and belonging to genera formerly 
regarded as foreign to the carboniferous limestone, such as Isocardia, 
Nucula, Pecten, Patella, Turritella, and Buccinum. Many species 
of Zoophytes and Crinoidea are also described and figured in this 
excellent monograph. 
We are indebted to Mr. Austen for a description of the South of 
Devonshire between the river Ex and Berry Head, and between the 
coast and Dartmoor, a district consisting of transition rocks, new red 
sandstone, greenstone, and trap. His speculations on the origin of 
the different formations and the causes which gave rise to the exist- 
ing features in the physical geography of the country, display much 
talent and are full of instruction. 
The structure of Devonshire has also furnished a fertile field of 
inquiry to Messrs. Sedgwick and Murchison since our last anniver- 
sary. They have attempted the difficult task of establishing a clas- 
sification of the older rocks so largely developed in that county. 
In every geological map hitherto published of Devonshire, all the 
stratified deposits of higher antiquity than the new red sandstone 
had been represented by one common color, the limestones being all 
included as integral parts of one great formation called greywacke.* 
But these gentlemen, after examining this region, announced at Bris- 
tol to the geologists assembled at the meeting of the British Asso- 
ciation, that the great mass termed greywacke, and previously undi- 
* The abstract of the Report of Messrs. Sedgwick and Murchison, published 
with a section in the Atheneum, August, 1836, and in other scientific journals, is 
the same as that written for insertion in the Proceedings of the Association. From 
that document, and from a written explanation of their views, which I obtained 
from the authors, the present observations are deduced. 
