158 Darwin, and after Darwin. 



as we well know, the opportunities which the geo- 

 logist has of discovering fossils are extremely limited, 

 if we consider these opportunities in relation to the 

 area of geological formations. The larger portion of 

 the earth's surface is buried beneath the sea; and 

 much the larger portion of the fossiliferous deposits 

 on shore are no less hopelessly buried beneath the 

 land. Therefore it is only upon the fractional portion 

 of the earth's surface which at the present time 

 happens to be actually exposed to his view that the 

 geologist is able to prosecute his search for fossils. 

 But even here how miserably inadequate this search 

 has hitherto been ! With the exception of a scratch 

 or two in the continents of Asia and America, 

 together with a somewhat larger number of similar 

 scratches over the continent of Europe, even that 

 comparatively small portion of the earth's surface 

 which is available for the purpose has been hitherto 

 quite unexplored by the palaeontologist. How enor- 

 mously rich a store of material remains to be 

 unearthed by the future scratchings of this surface, 

 we may dimly surmise from the astonishing world of 

 bygone life which is now being revealed in the newly 

 discovered fossiliferous deposits on the continent of 

 America. 



But, besides all this, we must remember, in the 

 second place, that all the fossiliferous deposits in the 

 world, even if they could be thoroughly explored, 

 would still prove highly imperfect, considered as a 

 history of extinct forms of life. In order that many 

 of these forms should have been preserved as fossils, 

 it is necessary that they should have died upon a 

 surface neither too hard nor too soft to admit of their 



