OF THE EARTH. 491 



those which is not admissible from any laws of me- 

 chanics or chemistry, known or supposeable : and 

 thence again it is inferred that the surface must have 

 been elevated in those places,, while, in certain cases, 

 we discover the elevating causes themselves, and have 

 even witnessed the fact. 



In the 15th, 16th, and 17th Chapters, I have ex- 

 plained this subject : but having done this for the first 

 time, and being thus compelled therefore to associate 

 many different facts, that I might disentangle the con- 

 fusion made by former geologists, I must here state 

 the cases which belong to the present view. They 

 are, first, those in which we find the bottom of the 

 ocean thus elevated, whether we can prove a partial 

 disturbance of the inferior strata or not, and where, at 

 the same time, we do not discover the elevating causes ; 

 and, next, those where we perceive the same fact ac- 

 companied by its causes. This is the twofold division 

 demanded under the present views ; because each is a 

 partial revolution, or set of revolutions, which we can 

 apparently separate in time: the case of Italy being an 

 example in one, and that of the Coral islands in the other. 

 But, under this enquiry, there are two desiderata yet 

 unfulfilled : the observations of Geologists being hi- 

 therto worthless as to both ; because they had neither 

 seen the causes nor understood the facts : having even 

 entirely overlooked the latter, except in two or three 

 instances, and misapprehended them when seen. 

 Under the arrangement and explanations which I 

 have here made, it must be hoped that they will here- 

 after supply this defect, and thus enable a future syste- 

 matical writer to fill up the sketch which I must leave 

 imperfect. These desiderata are, the periods of time 

 at which such partial revolutions took place, and 

 the places where they have occurred. As to the 

 former, we have seen them happen in our own day. 



