18 48.] MURCHISON ON THE STRUCTURE OF THE ALPS. 237 



have the remarkable fact, that in the subordinate marine masses many 

 of the shells are living species. 



This discrepancy in the evidences drawn from terrestrial and ma- 

 rine sources has already created divergent opinions respecting the age 

 of strata among naturalists. Thus, judging from the vertebrata found 

 in the older freshwater deposits of the Rhine and other parts of 

 Germany, where marine evidences are wanting, M. Herman von 

 Meyer would class as eocene that which other geologists call miocene, 

 and he has naturally referred to the miocene age those very (Eningen 

 freshwater and terrestrial strata so charged with lost types, but which, 

 as I now assert, were formed after the accumulations in which plio- 

 cene and living marine fossils occur. 



This persistence of marine forms during a period in which a whole 

 terrestrial fauna became extinct — a period it will be recollected when 

 the proportion of the known remains of the land in reference to those 

 of the sea was infinitely larger than in earlier times — may lead us to 

 be cautious in deciding on the age of a secondary rock by the mere 

 characters of its fossil vegetables (see p. 178). At all events, the con- 

 tents of the upper tertiary deposits of Switzerland compel us to admit, 

 that in any classification of a terrestrial formation by the more or less 

 prevalence of existing types, not even the youngest of those Swiss 

 strata at CEningen can be termed miocene or pliocene. So com- 

 pletely, indeed, do all its imbedded terrestrial animals seem to belong 

 to lost types, that we have not yet even authority to call them eocene, 

 although in reference to marine deposits they have been formed in 

 part out of the detritus of the marine eocene Alpine rocks ! In ren- 

 dering our science exact, we must, therefore, I apprehend, classify 

 strata deposited in fresh water or on land separately from those of sub- 

 marine origin. In reference to the tertiary sera, we can only speak 

 of the former, as older or younger land formations ; since it is mani- 

 fest, that (without a total disregard of the meaning of the words) 

 we cannot apply to them the terminology employed to designate the 

 tertiary marine stages*. 



Dislocations in the Alps. 



The previous pages having been chiefly devoted to the detection of 

 the order in which the formations have been accumulated, I now 

 invite attention to some examples of those grand phsenomena of con- 

 tortion and fracture of the strata which specially characterize these 

 mountains. By whatever causes produced, these derangements are 

 so great, that geologists accustomed to work in less troubled regions 

 could scarcely have ventured to hope, that the Alps would have been 

 found to explain any portion of i}iQ sniccession in the earth's deposits, 

 still less that they should contain, as I have endeavoured to show, 

 certain links to connect the secondary and tertiary rocks, which, if 



* The commingling of lost types of large terrestrial animals with those of 

 species scarcely distinguishable from our own in the rich tertiary deposits of the 

 sub-Himalaya chain, is, also, a splendid example of the difficulty of synchronizing 

 such terrestrial accumulations with the marine tertiary deposits named eocene, 

 miocene, and pliocene. 



VOL. V. PART I. S 



