DOCTRINE OF GEOLOGICAL CONTINUITY. 277 



not abolished by the elevation of tlie European Cretaceous area, but 

 was simply transferred to some other region. In tMs particular 

 case "we do not happen to know where this new area of deposition 

 may have been situated. It is quite certain, however, that in what- 

 ever area the Cretaceous animals of Europe took refuge, there rock 

 must have been deposited in course of time, though it does not 

 follow in any way that the rocks of the new area should have any 

 likeness in mineral composition to those of the later Cretaceous 

 period. If we should at any time discover these rocks, it may be 

 pretty safely predicted what we should meet with in the way of 

 fossils. We should find, namely, some characteristic Cretaceous 

 species, but with certain points of difference ; in addition there 

 would be a certain proportion of forms of life wholly unknown in 

 the Cretaceous rocks, and more or less resembling those of later 

 periods; and, lastly, thei^e would be a marked absence of certain 

 characteristic species of the chalk. In other words, such deposits as 

 we have been speaking of, would contain an assemblage of fossils 

 more or less interm.ediate in character between those of the Creta- 

 ceous period and those of the lowest tertiary beds (Eocene) which 

 rest upon the chalk. In point of fact, we have actually traces of 

 such deposits (in the Msestricht beds of Holland, the Pisolitic Lime- 

 stone of France, the Faxoe Limestone of Denmark, and the Thanet 

 Sands of Britain) ; and we find in these evident traces of such an 

 intermixture of cretaceous with tertiary types. 



It may be well here to consider for a moment how it is that we 

 may never hope to find a complete series of deposits intermediate 

 between any two great formations, such as the Cretaceous and Eocene 

 rocks. In the first place, only a limited portion of the earth has as 

 yet been properly examined, and we have therefore no right to 

 wonder that we have not yet hit upon the area to which the process 

 of rock forming may have been transferred at the close of the Creta- 

 ceous period in Europe. We have, however, every reason to expect 

 that we shall ultimately find formations which will have to be inter- 

 calated in point of time between the white chalk and the Eocene 

 rocks ; and, as before said, traces of such are already known to us. 

 Secondly, many of these intermediate deposits may have been 

 destroyed at some time subsequent to their formation by " denuda- 

 tion." Thirdly, many of these missing deposits may have been 



