32 Reviews—Daglish and Forster on the Permian Rocks. 
lithological types.’ It is not unlikely that Messrs. Daglish and 
Forster, in arriving at these conclusions, have been too much 
influenced by their observations in pit-sections of the Magnesian 
Limestone. Indeed, they imply that from the information thus 
derived they have come to their present opinions ; and they state 
that in pit-sections they have ‘frequently had before them sections 
of the entire deposit.’ This, however, is simply a mistake; for there 
is not a single pit in the Northern Coal-field that has ever passed 
through an entire section of the Magnesian Limestone. The majority 
of the pits penetrating the limestone are on the outcrop of its lower 
beds (Lower Limestone) ; some—Monkwearmouth, Ryhope, Seaton, 
Castle Eden, &c.—are on the outcrop of the middle member ; but 
there are none which commence on any part of the Upper Lime- 
stone; and, as this member has been bored into, by the Sunder- 
land and South Shields Water-company, at Cleadon, for a depth 
of 280 feet without reaching its base, and as we know it to be, by 
actual measurement, between 400 and 500 feet in thickness in another 
locality, it is evident that the pit-sections in Durham can give 
only an imperfect idea of the entire deposit. Taking pit-sections 
as their only guide in studying the structure of the Magnesian Lime- 
stone, the authors can never possibly comprehend the stratigraphical 
arrangement determined by King and Howse. Before they can 
place themselves in a position for judging whether that arrange- 
ment agrees with the facts of the case or not, they must see the 
whole of the formation to which it refers; and that they have 
not placed themselves in that position we feel perfectly satisfied, 
having too high an opinion of the authors’ capacity of observation 
and correct judgment to suppose them capable of coming to the 
conclusions they have published had they ali the facts before 
them. We are certain that had they gone into the field as prac- 
tical geologists, and examined carefully the Magnesian Limestone 
as it is to be seen at the surface, as well as from the subterranean 
point of view which the duties of their profession have given them, 
they would have discovered that the generalization of Professor 
King was neither ‘speculative’ nor ‘extremely hazardous,’ but the 
legitimate conclusion of good observation. We say this because we 
know from personal examination that the lithological characters do 
net alternate in the way that the authors suggest. But even did 
they so vary, we question the propriety of deciding the subdivi- 
sional arrangement of any fossiliferous formation without considering 
its paleontological as well as its purely geological data. Of such 
importance, indeed, has paleontological evidence now become that it 
would be just as judicious for a modern mining engineer to lift his 
coal with a one-horse gin as for a geologist to attempt to classify 
sedimentary rocks without referring to their fossils. Nevertheless 
this is what the authors attempt todo; for they wholly ignore the 
palzontology of the Magnesian Limestone. For aught they say 
to the contrary, there might not be a single fossil in it; or fossils 
might be of no more consequence than so many lusus nature. 
We have no desire to extend our criticism on the opinions which 
