Correspondence — Mr. Jukes-Browne — Mr. Kinahan. 237 



In Mr. Kinahan's former book, "Valleys and their Relations to 

 Fissures, etc.," the following passage occurs : " The first of these pro- 

 positions [that limestone once existed over the whole of S.W. Ire- 

 land] Mr. Jukes subsequently gave up. . . . This, however, does 

 not much affect the present subject [i.e. formation of river-valleys], 

 as some of the other rocks are nearly as easily denuded as limestone." 



I should feel obliged to Mr. Kinahan if he would explain the full 

 meaning of the extraordinary statement contained in the first of the 

 above quotations, and also how the latter passage is to be reconciled 

 with the former. 



I entirely fail to see how Mr. Jukes' theory depends on the 

 supposition that the Carboniferous Limestone once extended over the 

 South-west of Ireland, and if Mr. Kinahan will carefully re-read the 

 original paper in the Quart. Journ. Geol. Soc, vol. xviii., I think he 

 will see that he has been under a misapprehension regarding the 

 " supposed Limestone hills." There is only one passage in which 

 such hills are supposed, and this forms part of a hypothesis men- 

 tioned only to be presently dismissed as leading to utter absurdity 

 and confusion. The dominant ridges really involved in Jukes' 

 explanation are the great anticlinals of so-called Old Red Sandstone 

 separating the synclinal valleys in Cork and Waterford ; he supposes 

 the streams to have commenced the erosion of their channels along 

 the surface of a plain of marine denudation which sloped southwards 

 from these dominant ridges. 



I am aware that Mr. Kinahan has published his idea of the origin 

 of these and other valleys, and I have no desire to enter into a dis- 

 cussion regarding his peculiar views ; but I must protest against so 

 summary a dismissal of Jukes' well-considered theory. I need only 

 add that I am one of those who believe that it completely explains 

 the courses of many river- valleys both in England and Ireland. 



HlGHGATE, March 10. A. J. JukES-BrOWNE. 



PROF. HULL AND G. H. KINAHAN. 



Sie, — The statements of Prof. Hull in the Geological Magazine 

 for March, 1879, being mostly personal, I cannot think my 

 answering them would be any advantage to Science. My facts can- 

 not be disproved, and any one interested in the question can judge 

 which is right by examining the Irish rocks for themselves. As to 

 the supposed Permian, if Prof. Hull is mistaken, I am not bound 

 blindly to follow him ; and my opinion as to the age of the 

 rocks is backed by the opinions of Griffith and others, also by the 

 fossils found in the rocks. G. Henry Kinahan. 



Geological Survey of Ireland. 



OCCURRENCE OF EURYNOTUS IN THE CARBONIFEROUS 



LIMESTONE OF BELGIUM. 



Sir, — Prof, de Koninck has, in the recently published first part 



of his new great work on the " Faune du calcaire Carbonifere de la 



Belgique," p. 25, plate hi., described, under the name of Platy- 



somas (?) insignis, De Kon., a fish from the Carboniferous Limestone 



