1898.] Geology of Co. Water ford. 45 



Goresbridge, Co. Kilkenny. Its beaches are now the conglomerates, 

 and the finer material deposited in the lake form the sandstones which 

 are a familiar feature in this county. The floor of the lake continued to 

 sink, and the deposited material had attained to a thickness of over 

 3,000 feet, when the sea gained admission, and the Carboniferous era 

 was inaugurated. At first the deposits were terrigenous, but the sea 

 becoming more open, pure limestone began to be formed; this state of 

 affairs continued for a considerable time till an extensive area was 

 covered with this formation, which reached a thickness here of probably 

 1,800 feet. Of organisms which contributed to the making of this 

 limestone the most abundant were crinoids or sea-lilies ; and recent 

 research has proved the presence of siliceous sponge-spicules and 

 Radiolaria. Subsequently a shallowing of the waters took place, sandy 

 and pebbly deposits therein formed the Millstone Grit, and the encroach- 

 ment of the land on the sea formed lagoons. Around these, dense 

 jungles and forests arose, and all the conditions essential for the 

 production of coal-beds, which at this period were formed on a large 

 scale. None are now found on this district, having been denuded off 

 during the long interval between the Carboniferous and the Glacial 

 periods. A picturesque description of animal and vegetable life at this 

 time follows, and a comparison is instituted between the state of affairs 

 then, and the actual condition of the mangrove swamps of tropical 

 countries. The Post-Carboniferous history of Co. Waterford is next 

 dealt wnth. Earth-movements which took place at the end of the 

 Carboniferous period, bent the strata in this district into a series of folds 

 whose axes run east and west, depressed them below the sea, and when 

 subsequent upheaval brought these folds under the action of the waves, a 

 "plain of marine denudation " resulted. Continued upheaval elevated 

 this plain above sea-level, where it remained during untold ages exposed 

 to aerial denudation, which removed some 5,000 feet of strata. The 

 main physical features of the county as we find them at present were 

 produced in this interval ; though probably, prior to the Glacial epoch 

 the land stood some hundreds of feet higher than it does now. An 

 interesting account follows dealing w-ith the origin of the surface 

 features of the district. The history of the various rivers is traced from 

 their very beginning, when as "consequent" streams they flowed 

 southwards down the plain of marine denudation across the strike of 

 the Carboniferous and Old Red Sandstone beds. Later on "subsequent " 

 streams arose along the strike of these same beds, and in some cases 

 developed so rapidly as to become the main drainage system of the district, 

 cutting off" earlier-formed "consequent" streams and converting them 

 into mere tributaries. The erosion by these streams, and the changes in 

 their courses at various intervals, due to the rapid wearing away of the 

 softer strata, resulted in time in the formation of the mountain-ranges 

 as we now find them, the direction of the ranges being determined by 

 the east and west anticlinals produced about Permian times. The last 

 few pages of Mr. Reed's paper are devoted to an account of the Glacial 

 epoch ; and the evidence, which is abundant in this area, and on which 

 geologists rely to prove that submergence and upheaval of the land took 



