46 REPORT OF MEETINGS FOR I'QOl 



recently; and, indeed, it can easily be shown that the process of 

 upheaval is still going on. St. Yincent, St. Lucia, Martinique, 

 St. Pierre, are therefore, geologically speaking, geographical 

 features which are entirely of quite recent origin ; and this can 

 be shown to be the case with active volcanoes in general. 



The essential features to be borne in mind in the present 

 connection are these: — (I) The Windward Islands are situated 

 upon a ridge marginal to two oceanic depressions. (2) They 

 are of quite recent origin, so that the movements to which 

 both the downfolds and the correlative upfolds are due must 

 also be quite recent, or they may be even yet in progress. 

 (3) They are, of course, situated close to — within, in fact — a 

 large area of water contaiuing various substances in solution, 

 including compounds of Lime, Potash, Soda, Magnesia, etc. 



It would not be difficult to show that this concurrence of 

 circumstances has characterised all volcanoes, whether we have 

 regard to those which are active now, or whether we are 

 considering those which have become extinct. The question 

 that naturally arises, therefore, is whether we can connect 

 this concurrence of circumstances with any explanation that 

 would signify much in the present connection. It will not 

 be difficult to show that some such connection can be traced. 

 We may go farther and state that the presence of the volcanic 

 rocks on the shores of East Lothian is connected with oscillatory 

 movements of the Earth's crust, which occurred in these parts 

 many millions of years ago, and which, in all essential respects, 

 were identical with those which have a place in the geograph- 

 ical evolution of the volcanic features of to-day. 



Before considering these in detail, we shall give attention 

 to one or two more considerations bearing upon the causes of 

 volcanic action ; and, after that, go on to review what is 

 known of the history of the volcanic rocks to which these 

 remarks are intended more especially to apply. 



It may be as well to state here that I shall disregard the 

 old view that the volcanic action of all the later geological 

 periods has any necessary connection with any remains of 

 the primeval heat of the Earth. I shall go upon the assump- 

 tion* that volcanic action, in the main, is the direct result of 



* In which, probably, many persons will not agree with me. 



