Correspondence— D>\ C. Callaway— Prof. F. W. Hutton. 143 



and other authors, were shown to agree with these later Tertiary 

 andesites, both in their mineralogical constitution and in the peculiar 

 phases which they present to us. The latest Tertiary ejections were 

 shown in 1874 to bear the same relations to the five grand volcanoes 

 of the Western Isles which the chains of " puys " in Auvergne do to 

 the great central volcanoes of that district; and this conclusion is 

 strikingly confirmed by petrographical studies of which the results 

 were given in the present memoir. 



COERESPOUIDEITGE. 



AGE OF THE VOLCANIC SERIES IN SHROPSHIRE. 

 Sir, — In reference to the debate on a paper " On the Pebidian 

 Yoredale Series of St. Davids," read by Prof. C. Lloyd Morgan 

 before the Geological Society on the 8th inst., Prof. Blake is reported 

 to have said that recent work in Shropshire " had shown that there 

 was a volcanic series more satisfactorily classed with the Cambrian 

 than with the underlying series." Though I have some familiarity 

 with the older rocks of Shropshire, I am unable to call to memory 

 any volcanic series that can by any reasonable stretch of imagination 

 be referred to the Cambrian. If Prof. Blake refers to the Uriconian 

 system, surely the most recent work tends to throw it further back 

 from the Cambrian. But perhaps he will favour your readers with 

 a few words of explanation. Ch. Callaway. 



Sandore, Wellington, 

 Jan. IQlh, 1890. 



GROUND MORAINES. 



Sir, — I have just read in Professor James Geikie's Address to 

 Section C, British Association, " Swiss geologists are agreed that 

 the ground-moraines which clothe the bottoms of the great Alpine 

 valleys, and extend outwards sometimes for many miles upon the 

 low ground beyond, are of true glacial origin. Now these ground- 

 moraines are closely similar to the Boulder-clays of this country 

 [Britain] and Northern Europe." 



We have in New Zealand, also, extensive deposits of ancient 

 glaciers ; but I have never seen in New Zealand anything correspond- 

 ing to the Boulder-clays and stratified tills of Britain ; and if this 

 is correct, it would follow that Boulder-clays cannot be the ground- 

 moraines of glaciers. 



The subject is an important one, and I would suggest that the 

 British Association should send some one to New Zealand who is an 

 expert in Boulder-clays, to settle the question. Two months in 

 Otago, Canterbury, and Westland, between November and April, 

 and three months for the two voyages, would be sufficient time, and 

 the cost would not be more than £200 or £250. 



I do not know any more promising geological work at the present 

 day than a comparison of the glacial deposits of New Zealand with 



