Geological Society. 499 
to all the older sedimentary rocks of Devon and Cornwall, the au- 
thor states, that the fullest testimony is borne in the papers, con- 
taining their present views of the structure of those counties, of the 
source whence the suggestion was derived. 
Appended to the notice was a list of fossils, necessarily very in- 
complete, from the limited nature of the materials at the author’s 
command. It consisted of sixty-three species; twelve considered 
common to the Carboniferous and Devonian limestones, forty-two 
peculiar to the Devonian strata; and nine, seven of which are corals, 
common to the Devonian and Silurian formations; doubts were, 
however, entertained respecting the identification of the two species 
of shells. The author then observes,—should it be urged that it 
was unjustifiable to assume, from organic remains alone, the age of 
the Devonshire limestone, it may be replied, that in a district of 
which little in 1837 was positively known, which is cut off by the 
granite of Dartmoor from the only base line of the country, the 
culm measures of central Devon, proved in 1836 by Prof. Sedgwick 
and Mr. Murchison to be the representative of the true coal mea- 
sures, organic remains were the only test by which the age of strata 
so situated could be determined; and in support of his argument, 
he advanced the recent establishment in Cutch and the Desert to 
the east of it, from the examination of suites of fossils brought to 
England by Capt. Smee and Capt. Grant, and others procured by 
Colonel Pottinger at the request of Colonel Sykes, of a series of beds 
unquestionably of the age of the oolites of England, the fossils 
agreeing in their general characters with those of that geological 
epoch in this country, and being in many instances specifically undi- 
stinguishable. In this case, mineral characters and order of superpo- 
sition would have been valueless guides, for the rocks are totally differ- 
ent in character from those of the same age in England; and there 
was no predetermined series of beds from which an order of super- 
position could be derived. Another instance was noticed of the value 
of organic remains, if rightly applied, in determining the relative 
age of a distant region, and in this case of one inaccessible to 
Europeans, in the Ammonites obtained from the Tartar side of the 
Himalayan mountains. These fossils prove the existence in that 
unexplored country, of rocks of the secondary epoch, by possessing 
that peculiar character in the sutures, which is not found in Am- 
monites of any other epoch; they are moreover accompanied by Be- 
lemnites. 
In advocating the value of fossils, the author, however, begs it 
may be clearly understood, that he would not expunge from the 
geologist’s consideration, the aid to be derived from order of super- 
position, and under a right control, from the use of mineral compo- 
sition and lithological structure; and he would advise the observer 
not to depend upon his own limited sources of knowledge, but to 
seek the aid of the philosophical zoologist, who can teach him to 
reason justly on the distribution of animal life,—the accidents to 
which it is liable,—the changes which such accidents may produce, 
or the means provided by nature to resist them,—and on the effects 
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