DISLOCATIONS OF STllATA, 89 



tares are often accompanied by a separation of the 

 parts which were once continuous, that one portion 

 of a stratum occupies a higher or lower place than 

 another, and that this separation is often attended hy 

 a difference in the angle of inclination of the sepa- 

 rated parts, we have every proof that can be desired, 

 of an alteration in the positions of stratified rocks 

 since the period at which they Avere formed or conso- 

 lidated. Here we may safely reason from a part to 

 the whole ; from a single member in a connected 

 train of phenomena, to all those by which it is 

 accompanied. 



In the nature of the materials, of which many of 

 the inclined strata are formed, we find further proofs 

 of their elevation. It is elsewhere shown, that many 

 of them are composed of substances once separate ; of 

 sand, and of fragments of more antient rocks, conso- 

 lidated by causes, respecting which it has been in- 

 quired in its proper place. (Chap, xii.) It is admitted 

 that the finer materials, at least, need not necessarily 

 have been deposited on a horizontal plane ; but that 

 they might rest beneath water at angles of considera- 

 ble inclination, waiting for the period of their conso- 

 lidation. But this admission is far too limited to be 

 of use in explaining the cases that occur. It is noto- 

 rious that the conglomerate rocks, which form such 

 conspicuous strata in many countries, and which 

 prevail chiefly at the boundary which separates the 

 strata called secondary from the primary, are often 

 found in positions, not only highly inclined, but 

 absolutely vertical. As the materials of these are 

 often of such bulk as to weigh, ev<m many hundred 

 pounds, it is evident that the original position of the 

 strata which contain them, must have been hori- 

 zontal. 



