Correspondence — Prof. E. Hull. 131 



the Survey Memoir on the district in question, I naturally inferred 

 that he was also responsible for the Map. He informs me, however, 

 that the Map issued to me by the agents of the Irish Survey is an 

 obsolete edition with which he had nothing to do. I am happy 

 to vindicate Mr. Kinahan's consistency, but I cannot think that 

 geologists will be greatly benefited by being supplied with Maps 

 which a prominent member of the Survey declares to be superseded. 



Wellington, Salop, Bee. 22, 1881. C. Callaway. 



LAURENTIAN EOCKS IN DONEGAL. 



Sir, — It is with great reluctance that I feel obliged to reply to the 

 letter of Mr. Kinahan which appears in the current Number of the 

 Geological Magazine, as it might be supposed by some who may 

 have read this letter that I have been endeavouring to take from my 

 late friend and preceptor. Professor Jukes, the credit of having first 

 made the discovery of Laurentian rocks in Donegal, and in other 

 parts of Ireland — a charge which I unequivocally deny. 



On seeing Mr. Kinahan's letter in the December Number of the 

 Geol. Mag. in which he states (p. 575), " While in reality the ques- 

 tion " (of the existence of Laurentian rocks in Donegal) " has not 

 been worked out since Jukes first suggested they were Laurentian 

 rocks," I wrote to Mr. Kinahan to ask for his authority for this 

 statement, inasmuch as I had, when reading over papers on the 

 Geology of Donegal, been unable to find anything to support it. 

 The following is a copy of my letter and of Mr. Kinahan's reply : — 



" Dublin, 6 Bee. 1881. 



" Sir, — In the current number of the Geological Magazine there appears a 

 letter in which you state that ' In Donegal we are now told that undoubtedly there 

 are Laurentian rocks, while in reality the question there has not been worked out 

 since Jukes first suggested they were Laurentian rocks.' As I have been unable to 

 discover any suggestion to the above effect in the writings of Professor Jukes, I 

 would be obliged to you to inform me on what authority you have made the above 

 statement. — I am, Sir, your obedient servant, 



"To G. H. Kinahan, Esq. Edwakd Hull." 



The following is Mr. Kinahan's reply (by post-card) ; — 



" Letters like that about the Geol. Mag. have no official bearing. I may however 

 tell you to read the first chapter of the Geol. of Ireland written and in print in my 

 book before the Laurentian craze set in. 



" 7. xii. 81. G. H. Kinahan." 



On referring to the passage in Mr. Kinahan's book, all I can find 

 bearing on the subject is as folloAvs : — " Eocks older than the Cam- 

 binan formation are not known in Ireland ; but Jukes suggested that 

 some of the highly metamorphosed rocks of the North of Ireland 

 might possibly be Pre-Cambrian." 



It would appear, therefore, that in making the statement con- 

 tained in the Geol. Mag. for December, Mr. Kinahan quotes from 

 himself, but there is no reference to any published expression of Mr. 

 Jukes' views here or elsewhere. 



It would appear, however, from Mr. Kinahan's second letter, that 

 the whole statement rests on his recollection of conversations on the 



