1 88 The Irish Naturalist. 



frequency with which the later rocks have been deposited 

 against cliffs and hills of the older ones. In the Co. Donegal, 

 and neighbouring portions of I^ondonderry and T>Tone, future 

 explorers will have to allow that the younger rocks in places 

 were accumulated against cliffs and hills of the older; this is 

 conspicuous at Knockanteenbeg; the description and section 

 of it are, however, omitted from the memoir. My con- 

 clusions are controverted, and will be controverted, until the 

 results of inversions due to over-thrusting are full}^ studied 

 and understood. In this area there were at least three dis- 

 tinct times of over- thrusting : — first, an over- thrusting of the 

 Kilmacrennans ; second, an over- thrusting of the rocks in the 

 middle terrane; and third, an over-thrusting of the rocks of 

 the upper terrane. The latter is very conspicuous in Innish- 

 owen, when the rocks of the middle and lower terranes suffered 

 very little in comparison. 



In the Carrick mountain, Wicklow, and in South Wexford it 

 is conspicuously seen that the Ordovicians were accumulated 

 against cliffs of the Oldhamians (Algonkians?) In the diffe- 

 rent basins of Silurians there are ocular proofs of cliff and 

 hill-margins, while the Carboniferous sea was more or less an 

 archipelago, the islands of older rocks being numerous in the 

 area. 



Sir A. Geikie also ignores the adjuncts of the different ter- 

 ranes. Years ago it was pointed out by David Forbes that each 

 has its specific accompaniments, which law laid down by him 

 has been confirmed by all subsequent investigators. Each ter- 

 rane has as adjuncts its special traps, occurring either as beds 

 or protrudes ; these will not be found in a newer terrane, and 

 if in an older they occur, not as an adjunct but as an intrude, 

 and, in general, of a more or less granitic nature. These special 

 adjuncts of the different terranes in the Co. Donegal are very 

 constant, assisting considerably to prove their respective 

 ages. It is unnecessary to mention what they are, as they 

 are specially described in my previous paper. 



NOTICE. 



A series of papers on "The Earthworms of Ireland," will be 

 commenced in the January number of the Irish Natiu^alist, by 

 Rev. H11.DERIC Friend, F.L.S., of Idle, Bradford, Yorkshire. 



Mr. Friend will be grateful for worms from all parts of the 

 country. They should be sent alive in damp earth or moss, in 

 metal boxes. Packages should be marked "Natural History 

 Specimens." 



