to the Mineral Structure of the South of Ireland. 165 



places referring to the large geological map, in the first of 

 which he states, " that his paper was drawn up before he 

 had seen another geological map on a large scale, published 

 in 1839;" and he observes, a that as the alterations that have 

 been made in the new map do not materially interfere with 

 the course of his argument, which in the first instance bears 

 on the map attached to the outline, he has left the text un- 

 altered." Now in his text Mr. Weaver does not confine his 

 observations to the outline and small geological map, but re- 

 fers equally to the three papers read by me before the British 

 Association, and the Geological Societies of London and 

 Dublin, the whole being compared with the small geological 

 map, though at the period of the publication of his paper in 

 April 1840, my large geological map had been in the posses- 

 sion of the London Geological Society for eleven months, 

 and was to be seen exhibited in Mr. Gardner's, in Regent 

 Street, for upwards of a year ; so that it does appear extra- 

 ordinary, that Mr. Weaver, who in the commencement of his 

 paper alludes to my several communications above-men- 

 tioned, in each of which my large geological map is men- 

 tioned, should not have seen it when he drew up his paper 

 for the Philosophical Magazine. 



With this explanation I will conclude my observations on 

 the subject of the discrepancies noticed by Mr. Weaver be- 

 tween my small geological map, and the sections and papers 

 intended to illustrate the large one. 



In comparing Mr. Weaver's geological map of the south 

 of Ireland with mine (the large one), it must be admitted 

 that the differences are very considerable, both in the great 

 scale and in the detail. The latter is not to be wondered at, 

 as I possessed much better maps, and had many opportunities 

 of examination in almost every locality ; but in regard to the 

 great features, some explanation appears to be necessary. 

 Mr. Weaver considers the whole of the schistose strata si- 

 tuated to the south of the river Suire in the county of Water- 

 ford, and thence to the south coast of the county of Cork, to 

 belong to the transition series, on the northern part of which, 

 particularly on the summits of the Kuockmildownand Mona- 

 voullagh mountains, strata belonmno; to the old red sandstone 

 series are superimposed in an unconformable position ; and 

 that the limestone of the valleys of the rivers Suire and Black- 

 water belong to the carboniferous series, while that of the 

 valleys of the rivers Bride, Lee, &c. is transition, and alter- 

 nates with the transition slate. 



According to my view, the transition slate within the above- 

 mentioned limits is confined to the dark gray slate district 



