<MAf. vii TIU N \ \N'D USE OF FOSSILS 93 



better for his work. The broad outlines of William 

 Smith's days have to be filled in by more minute and 

 exhaustive work now. 



In fine, the field-geologist will find in all quarters of 

 the world that an acquaintance with fossils can be turned 

 to profitable account. It enables him at the outset to 

 ^ definitely the relative age of the rocks 

 among which he is engaged, and thus affords means of 

 comparison with the corresponding rocks of other 

 countries. Where his labours are of no ambitious kind, 

 but where he works for the quiet pleasure and open-air 

 life of the pursuit, the study of organic remains affords 

 htm an endless fund for delightful meditation. It shows 

 him at one place evidence of an old sea-bottom, in the 

 strata where marine remains are crowded together. At 

 another locality it brings before him, in fresh-water shells 

 and other forms, the traces of long-vanished lakes and 

 rivers. At a third spot it reveals, in successive layers of 

 compressed vegetation and hardened loam, the gradual 

 depression and submergence of old forest-covered lands. 

 In such cases, fossils suggest the lines along which his 

 further search should be prosecuted for additional corro- 

 borative testimony as to the ancient aspects of the ci 

 in which he is at work. The land-plants, for example, 

 lead him to look for fresh-water forms of life, for sun- 

 cracked and rain -pitted surfaces of rock ; while the 

 occurrence of marine forms of life prompts him to search 

 for other proofs of the ancient dominion of the 



