Ch. I.] 
METHODS OF THEORIZING IN GEOLOGY, 
3 
and to blunt the keen edge of curiosity, than this assumption 
of the discordance between the former and the existing causes 
of change. It produced a state of mind unfavourable in the 
highest conceivable degree to the candid reception of the evi- 
dence of those minute,, but incessant mutations, which every 
part of the earth's surface is undergoing, and by which the 
condition of its living inhabitants is continually made to vary. 
The student, instead of being encouraged with the hope of 
interpreting the enigmas presented to him in the earth's struc- 
ture, — instead of being prompted to undertake laborious 
inquiries into the natural history of the organic world, and 
the complicated effects of the igneous and aqueous causes now 
in operation, was taught to despond from the first. Geology, it 
was affirmed, could never rise to the rank of an exact science, — 
the greater number of phenomena must for ever remain inex- 
plicable, or only be partially elucidated by ingenious conjec- 
tures. Even the mystery which invested the subject was said to 
constitute one of its principal charms, affording, as it did, full 
scope to the fancy to indulge in a boundless field of speculation. 
The course directly opposed to these theoretical views con- 
sists in an earnest and patient endeavour to reconcile the former 
indications of change with the evidence of gradual mutations 
now in progress ; restricting us, in the first instance, to known 
causes, and then speculating on those which may be in activity 
in regions inaccessible to us. It seeks an interpretation of 
geological monuments by comparing the changes of which they 
give evidence with the vicissitudes now in progress, or tvhich 
may be in progress. 
We shall give a few examples in illustration of the practical 
results already derived from the two distinct methods of theo- 
rizing, for we have now the advantage of being enabled to 
judge by experience of their respective merits, and by the rela- 
tive value of the fruits which they have produced. 
In our historical sketch of the progress of geology, the reader 
has seen that a controversy was maintained for more than a 
century, respecting the origin of fossil shells and bones- — were 
B 2 
