Correspondence— R. Askington BuUen — Dr. Callaway. 191 



of paired resultant strains, acting along N.E.-S.W. and N.W.-S.E. 

 directions, the precise directive angle varying in proportion as the 

 east-west or the north-south stresses due to crust compression were 

 the more powerful, and also in accordance with particular local 

 modifications of the regional strains. At the close a vote of thanks 

 was cordially given to Mrs. Gordon. 



ooI^I^:BS IPO 3:vrnD:Ei<ro :e . 



EOLITHS FROM SOUTH AND SOUTH-WEST ENGLAND. 

 Sir, — Kindly insert the following correction and addition to my 

 paper on " Eoliths from South and South- West England " in the 

 March number. 



1. Corrigendum. — Instead of Bat's Corner read Kettle's Corner, 

 Parsonage Farm (Chapel Croft Field), near Ash. Mr. Harrison 

 informs me that it is so marked in the 6 inch map of the district. 

 Bat's Corner was the name given me on December 24th, 1894, when 

 1 visited the pit with Mr. Harrison, but as tenants change so do the 

 names of their farms. Probably Kettle was the name of a former 

 tenant. 



2. Addendum (Bibliography), with sincere apologies for the 

 omission. 



1899. Newton, H. T. — Presidential Address to tlie Geologists' Association, 

 February 5tli, 1897 : Proc. Geol. Assoc, vol. xv, pp. 69-72. 



1902. Haddon, A. C. — "Early Man and his Life," third paper: National Home 

 Reading Union Magazine, p. 45. 

 Pyrford, March Wi, 1903. R- ASHINGTON BuLLEN. 



THE ORIGIN OF THE ARCHiEAN ROCKS. 



Sir, — Some references to the Archaean rocks made by Mr. G. W. 

 Bulman in the Geological Magazine for March (p. 126) call for 

 a word of comment. I do not understand what he means by " pre- 

 Archsean deposits." There are no rocks older than the Archaean, 

 whether we use the term as equivalent to " pre-Cambrian " or 

 limit it to the " Fundamental Complex." Then he remarks that 

 " Geologists are yet sorely perplexed with the problem of the 

 Archaean rocks. They have not yet decided whether they are 

 metamorphosed ordinary sediments, [or ?] part of the original 

 solidified crust of the earth, or chemical precipitates from a hot 

 primitive ocean." But these alternatives are not the problem. 

 There is no perplexity whatever about a large proportion of the 

 Archaean rocks. The Longmyndian and Torridonian are known to 

 be mainly sedimentary; the groups identified as Pebidian, Uriconian, 

 and Charnian are known to be predominantly volcanic; and the 

 rock-masses called Malvernian and Hebridean are generally admitted 

 to be igneous plutonics. A similar variety of origin has also been 

 ascertained with respect to many of the Archaean rocks of North 

 America, Bohemia, and elsewhere. There are, of course, some 

 Archaean rock-groups whose genesis has not yet been determined 

 with certainty; but these are only a. part of "the problem of the 

 Archaean rocks." C. Callaway. 



Cheltenham, March 5fh, 1903. 



