1907. 



Hinch. — Cork Conference. — Geology. 



263 



slates and sandstones of the Upper portion of the same system, 

 the fossils of which point to the belief that they were formed 

 in lakes of fresh-water origin. The Old Red is followed con- 

 formably by a series of deposits of the Carboniferous system, 

 grits, shales, slates, and a strong development of limestone, 

 all apparently conformable, and all yielding a large number 

 of marine fossils. With the close of the Carboniferous times 

 came the wide-spread and intense earth movements known as 

 Hercynian, which threw the existing strata into a series of 

 east-and-west folds over a large portion of West and Central 

 Europe; these earth movements also affecting Ireland, throwing 

 the sandstones and limestones into a series of east-and-west 

 folds which to this day dominate the structure of Southern 

 Ireland. With the cessation of the earth movements com- 

 menced an era of denudation which ended in the land forming 



SECTION #ROM BANTRY BAY TO KH,I<ARNEY. 



A. Old Red Sandstone. B. Carboniferous Limestone preserved in 

 synclinals. 



a plain (possibly of marine denudation) sloping from north to 

 south, and on this plain the primary drainage would cut from 

 north to south across sandstone, shale and limestone for some 

 time without distinction ; so that when differential erosion 

 commenced to work faster (by chemical solution) on limestone 

 than on the harder sandstone, some at least of the original 

 north and south channels would be sufficiently advanced to 

 dominate whatever lateral west-and-east drainage-lines subse- 

 quent erosion might develop. This subsequent erosion has 

 produced two effects — first, the formation of those east-and- 

 west valleys in the limestone, bounded by east-and-west 

 uplands of sandstone, which are so characteristic of the South 

 of Ireland ; and, consequently, of a series of rivers which flow 



