146 THE GEOLOGIST. 



influence of a cuiTent, the character of the resulting structure must 

 depend upon the depth of the water, the velocity of the current, the 

 natui-e of the deposits, and the rate of deposition. Xow, 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 

 search for the key. At one time no one would have thought it 

 possible to ascertain the nature and habits of an extinct animal fi'om 

 the examination of a few bones or teeth ; but Palseontology has now 

 been so perseveringly elaborated by able investigators that we look 

 upon this as a matter of course. The 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 rocks, 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 appear to be more diflficult, 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 

 cmTent, and the rate of deposition, with more or less accui'acy, fii-om 

 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 effort 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 imd origin of rocks. Those which I 



