110 PROCEEDINGS OF SOCIETIES. 



times, as I said before, consists of two parts : the upper, which is clearly 

 tied into and inseparable from the Carboniferous system ; and the lower, 

 which is as clearly associated with the Silurian ; and as Nature separated 

 them by one of her greatest chasms, so they ought to be separated by 

 man. The name should undoubtedly be retained for one of them ; but 

 whether should it be the upper or the lower ? My views lead me to 

 prefer keeping the name to the upper, and I shall state why. 



In the early days of Geology the division above alluded to was not 

 recognised in England, and the two were packed together where they 

 happened to be in contact, and said to be 10,000 feet thick. Indeed, 

 this may be said to be the case up to the present time. The carboni- 

 ferous part, however, is far more general in the British Islands than 

 the brownstone, which was included with it in certain districts by mis- 

 take or oversight, for want of being recognised. So far, then, as prece- 

 dence goes, I should say the upper or the base of the Carboniferous 

 should retain the name, and let the Silurian, or lower part, be provided 

 with a new name. I have called it brownstone, to distinguish it from 

 the upper band of rock, but I shall be happy to adopt a better name 

 with the majority of geologists, when it may be found. I do, how- 

 ever, think it highly objectionable to call the two upper and lower 

 Old Red Sandstone, as I have lately heard them called, because 

 the upper is the base of the Carboniferous formation ; it lies, as 

 before stated, indiscriminately upon mica slate, clay slate, gray or 

 green grit, primary limestone, quartz rock, porphyry, greenstone or 

 granite, in all which cases, though there is an upper, there is no 

 lower sandstone in contact to keep it company as a counterpart. The 

 Cambrian rocks have been made upper and lower, but they are one 

 great group divided. It is so also in the Silurian. There are upper and 

 lower oolite, and lias, and chalk, and tertiary, but they are always parts 

 of the same group. To make these two sandstones upper and lower, 

 where the lower is absent in nine cases out of ten, and when it is always 

 a rock of another geological epoch, does not appear to me to be either an 

 eligible association or nomenclature. 



About Dingle and other parts of the south of Ireland the green, 

 gray, and brown grits, and similarly coloured slates, are so intimately 

 associated by interstratification with each other in thick and thin bands 

 and beds, as to form one inseparable group. The rocks about Brecon in 

 "Wales are exactly similar. It therefore appears that the old name 

 graywacke would not be still unsuitable for this group. It would have 

 the merit of keeping out novelty, and abiding by the first name given to 

 those rocks — a thing much to be desired in Geology as well as in Pa- 

 laeontology. 



Regarding the arrangements made in pars. 1 and 4, the Old Red Sand- 

 stone is in its proper place. The Yellow Sandstone is a part of the same, 

 that ought not to be made a separate subdivision. The Lower Limestone 

 is the lower part of the Limestone. The Calp, I believe, is a pure fiction. 

 The author himself, at the quotations No. 8, 10, and 11, admits it does not 

 exist in the south of Ireland. I expect to be able to show that it is 



