274 THE .POORNESS OF OUR Chap. IX, 



length of time for llicir Jiccuinuliilion, are entirely destitute of 

 organic remains, witliout our being able to assign any reason : 

 one of tlic most striking instances is that of the Flysch forma- 

 tion, -wliich consists of shale and sandstone, several thousand, 

 occasionally even six thousand feet, in thickness, and extending 

 for at least 300 miles from Vienna to Switzerland ; and, al- 

 though this great mass has been most carefully searched, no 

 fossils, except a fcAv vegetable remains, have been found. 



"With respect to the terrestrial productions which lived 

 during the Secondary and Paleozoic periods, it is superfluous 

 to state that our evidence from fossil-remahis is fragmentary 

 in an extreme degree. For instance, not a land-shell until quite 

 recently was known belonging to cither of these vast periods, 

 with the exception of one species discovered by Sir C. Lyell 

 and Dr. DaAvsou in the carboniferous strata of North Amei'ica, 

 of which shell above a hundred specimens have now been col- 

 lected. In regard to mammiferous remains, a single glance at the 

 historical table published inLyell's Manual will bring home the 

 Iruth, how acciilental and rare is tlicir preservation, far better 

 than pages of detail. Nor is their rarity surprising, when we 

 remember how large a proportion of the bones of tertiary mam- 

 mals have been discovered either in caves or in lacustrine 

 deposits; and that not a cave or true lacustrine bed is known 

 belonging to the age of oiu- secondary or paleozoic formations. 



But the imperfection in the geological record largely results 

 from another and more important cause than any of the forego- 

 ing ; namely, from the several formations being separated from 

 each other l^y wide intervals of time. This doctrine has been 

 most emphatically admitted by many geologists and paleon- 

 tologists, who, like E. Forbes, entirely disbelieve in the change 

 of species. When we see tiie formations tabulated in written 

 works, or when we follow them in Nature, it is diihcult to 

 avoid believing that they arc closely consecutive. But we 

 know, for instance, from Sir R. Murchison's great work on Rus- 

 sia, what wide gaps there are in that country between the 

 superimposed formations ; Sf) it is in North America, and in 

 many otlier parts of the world. The most skilful geologist, if 

 his attention had been confined exclusively to tliese large ter- 

 ritories, Avould never have suspected that, during the periods 

 which were blank and barren in his own country, great piles 

 of sediment, charged Avith new and peculiar forms of life, had 

 elsewhere been accumulated. And if, in each separate territory, 

 hardly any idea can be formed of the length of time which has- 



