66 PALEOZOIC TIME. [CHAP. V. 



sites of the desiccated lakes ; through these plains ran the 

 rivers in deep and narrow channels, while on the mountain 

 slopes piles of debris were prepared by the agencies of dis- 

 integration and detrition. It is, indeed, not unlikely that 

 much of the material forming the conglomerates of the 

 Lower Carboniferous series was originally prepared by sub- 

 aerial agencies, and was only rearranged by the waters of 

 the later epoch. 



A reverse movement at length set in toward the end of 

 what must be called the Devonian period ; portions of the 

 old lake-basins were again filled with water, the area of 

 which widened and deepened as the land sank ; torrents 

 washed in the detritus of the land, and the material thus 

 collected became the conglomerates and sandstones of the 

 Upper Old Red and Lower Carboniferous series. 



This depression led to the formation of a large lacus- 

 trine area in the south-west of Ireland, spreading over 

 the tracts now known as the counties of Clare, Limerick, 

 Kerry, Cork, Waterford, Tipperary, and Kilkenny. Its 

 northern shore appears to have been somewhere along the 

 parallel of Galway Bay ; the Granitic and Ordovician rocks 

 of Wicklow, Carlow, and Wexf ord formed its eastern boun- 

 dary, while how far it extended to the south and west we 

 have no means of knowing, except that in the Dingle and 

 Kenmare districts we appear to be approaching its western 

 shores. From Dingle to Thomastown in Kilkenny is a 

 distance of 135 miles, and from G-alway Bay to the Old 

 Head of Kinsale is 108 miles; this would form a fine 

 sheet of water, but even if it stretched another 100 miles 

 to the southward, it would only have been about half the 

 size of the modern Lake Superior. 



In this lake were laid down the strata described on p. 

 58, and at the epoch of the Kiltorcan beds, with their 

 abundant remains of plants, it is evident that its shores 

 were bordered by tracts of fertile land, on which grew the 



