CHAPTER I. 

 THE STARTING-POINT. 



AN explorer trudging along some line of coast, or traversing 

 some mountain region, may now and then reach a pro- 

 jecting headland, or bold mountain spur, which may enable 

 him to command a wide view of shore and sea, or of hill and 

 valley, before and behind. On such a salient point he may 

 sit down, note-book and glass in hand, and endeavour to cor- 

 relate the observations made on the ground he has traversed, 

 and may strain his eyes forward in order to anticipate the 

 features of the track in advance. Such are the salient points 

 in a scientific pilgrimage of more than half a century, to which 

 I desire to invite the attention of the readers of these papers. 

 In doing so, I do not propose to refer, except incidentally, to 

 subjects which I have already discussed in books accessible to 

 general readers, but rather to those which are imbedded in 

 little accessible transactions, or scientific periodicals, or which 

 have fallen out of print. I cannot therefore pretend to place 

 the reader on all the salient points of geological science, or 

 even on all of those I have myself reached, but merely to lead 

 him to some of the viewing-places which I have found particu- 

 larly instructive to myself. 



For similar reasons it is inevitable that a certain personal 

 element shall enter into these reminiscences, though this auto- 

 biographical feature will be kept as much in the background 

 as possible. It is also to be anticipated that the same subject 



