4 TOWN GEOLOGY. 



the relative age of rocks by the fossils found in them, 

 which he can now, happily, study in many local 

 museums ; and he may be certain, for the rest, that all 

 rocks and soils whatsoever which he may meet have 

 been laid down by the agents, and according to the 

 laws, which I have tried to set forth in this book ; and 

 these only require, for the learning of them, the 

 exercise of his own observation and common sense. 

 I have not tried to make this a handbook of geo- 

 logical facts. Such a guide (and none better) the 

 young man will find in Sir Charles LyelPs t( Student's 

 Elements of Geology." I have tried rather to teach 

 the method of geology, than its facts ; to furnish the 

 student with a key to all geology, rough indeed and 

 rudimentary, but sure and sound enough, I trust, to 

 help him to unlock most geological problems which he 

 may meet, in any quarter of the globe. But young 

 men must remember always, that neither this book, 

 nor all the books in the world, will make them geo- 

 logists. No amount of book learning will make a man 

 a scientific man ; nothing but patient observation, and 

 quiet and fair thought over what he has observed. 

 He must go out for himself, see for himself, compare 

 and judge for himself, in the field, the quarry, the 

 cutting. He must study rocks, ores, fossils, in the 

 nearest museum ; and thus store his head, not with 

 words, but with facts. He must verify as far as he 

 can what he reads in books, by his own observation ; 

 and be slow to believe anything, even on the highest 

 scientific authority, till he has either seen it, or 

 something like enough to it to make it seem to him 

 probable, or at least possible. So, and so only, will he 

 become a scientific man, and a good geologist ; and 



