4,56 ON THE SUCCESSIVE FORMS 



difficulty, the views which it is intended here to lay 

 before him. In a certain sense, these form a sum- 

 mary of some parts of this work. The subject in- 

 deed still abounds with difficulties which I do not 

 pretend to remove ; but if the facts which bear on 

 this important train of events shall here be arranged 

 in a manner somewhat more comprehensive, this 

 chapter will have fulfilled all that it proposes to exe- 

 cute. 



On the Evidences of Revolutions in the Glole. 



The marks of great changes which the earth con- 

 tains, consisting in the successive deposition of new 

 strata, under circumstances that prove the existence 

 of intermediate intervals, imply successive periods of 

 repose, interrupted by revolutions indicating the ex- 

 ertion of enormous forces. During repose, the strata 

 were formed ; in the intervals, they were displaced. 

 If any of these revolutions can be shown to be uni- 

 versal, it will follow that the whole surface of the 

 earth has been changed once or more : if, on the con- 

 trary, they are only partial, it cannot be concluded 

 that the changes, or actions, on which they de- 

 pended, however extensive, were of a nature to in- 

 volve the entire globe. The evidences for these revo- 

 lutions and alterations, must be sought in the changes 

 or reversals of position exhibited by approximate 

 beds, in that part of the composition of strata which 

 indicates the existence of previous rocks, and in the 

 presence and position of imbedded organic fossils. 



From the mode in which alluvial materials of dif- 

 ferent kinds are now deposited beneath water, and 

 from the general doctrines of stratification formerly 

 examined, it has here been concluded, that a series 

 of strata consecutively parallel, using that term in a 



