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XXXIII.— PALEOZOIC ROCKS OF GALWAY AND ELSE- 

 WHERE IN IRELAND, SAID TO BE LAURENTIANS. 

 By G. H. KINAHAN, m.k.i.a., &c. With Plates XXX., XXXI , 



AND XXXII. 



[Read, May 15th, 1882,] 



It is well known to Irish geologists that Jukes, years ago, 

 suggested that some of the rocks of Donegal might be of Lauren- 

 tian age ; while King, of Gal way, made a similar suggestion in 

 reference to the rocks of Bennabeola, or the Twelve Pins* of 

 Connemara. Jukes published this opinion in his geology (1862), 

 to which I refer in the " Geology of Ireland." Subsequently, T. 

 Sterry Hunt, in a paper on metamorphic rocks read before the 

 Royal Geological Society in 1863, stated that many of the Donegal 

 rocks appeared to him to be lithologically identical with those of the 

 American Laurentians ; while at the same time he pointed out 

 that other rocks from the same area " cannot be distinguished 

 from those which characterize the altered Palaeozoic strata of 

 America," which are later than the Laurentian. 



In March, 1881, after the question of the possibility of Lauren- 

 tian rocks occurring in Ireland was mooted by Dr. Hicks and 

 others, I wrote a paper pointing out all the different tracts of old 

 rocks in Ireland having lithological characters more or, less 

 similar to those of the American Laurentians, but at the same 

 time I showed that they were also very similar to the American 

 •metamorphosed Huronians, (Lower or Cambro-Silurians.)*f- Dr. 

 Hicks had previously suggested that my " supposed upper Cam- 

 brians," in the coimty Tyrone, to the eastward of Omagh, might 

 be Laurentians ; while still more subsequently Drs, Callaway 

 and Hull published that they had discovered Pre-Cambrians 

 in Wexford, Mayo, and Donegal, 



Counties Donegal, Tyeone, and Mayo. 



In connexion with the Donegal rocks, I have carefully studied 

 all the statements published, and cannot see that their claim| to 

 the title of Laurentians has been satisfactorily proven ; on the con- 



* Called Twelve Stacks or Pins "by the mariners coming in from the maine" (O'Flaherty, 

 History of Hiar Connaught). 



■\ Tme MS. of this paper was mislaid, and conseqixently it did not appear in the 

 " Geological Magazine" until September, 



X Dr. Hull. Scientific Transactions, Eoyal Dublin Society, Vol, i., Ser, ii., page 24.3. 



