146 
THE GEOLOGIST. 
influence of a current, the character of the resulting structure must 
depend upon the depth of the water, the velocity of the current, the 
nature of the deposits, and the rate of deposition. Now, I argue that 
all these are more or less intimately concerned in the production of 
eveiy bed of rock, and that the various structures which I have 
described are so related to them by definite and unalterable physical 
laws, that, in many cases, the whole secret of its formation is locked 
up and preserved for our information, if we will but perseveringly 
seai'ch for the key. At one time no one would have thought it 
possible to ascertain the nature and habits of an extinct animal from 
the examination of a few bones or teeth ; but Palaeontology has now 
been so perseveringly elaborated by able investigators that we look 
upon this as a matter of course. Tiie laws of the organic world are 
surely no more definite and exact than those of mechanics and hydro- 
dynamics involved in the formation of stratified roeks, that geologists 
should place full confidence in one and so far neglect the other as too 
often to fear to attempt to deduce from them equally definite and 
exact conclusions. The problems may ajjpear to be more difficult, and 
their solution may, and certainly does, require a very different kind of 
study and train of thought ; but that is no reason why its solution 
should not be attempted. My opinion is, that the various structures 
which I have described are so intimately connected with the circum- 
stances under which they were formed, that nothing but perseverance 
is required to enable us to determine the depth and velocity of the 
current, and the rate of deposition, with more or less accuracy, from 
the existing peculiarities of ancient stratified rocks. If there be only 
an apparent probability of doing this, it is surely better to make the 
attempt and fail than to be content with our present ignorance and 
to make no eSbrt at all. Even at present the facts are sufficiently 
distinct to enable us to form tolerably satisfactory conclusions 
respecting the relative depth and velocity of the current and the rate 
of deposition, and to perceive that the knowledge of their actual value 
would enable us to make a very great advance in physical geology. 
For this purpose many experiments will be requisite, which I hope 
I shall be able to make, and which I should have made before now 
if I had not been induced to follow out other inquiries involved 
in the study of the structure and origin of rocks. Those which I 
I 
I 
