CHAP. V.] DEVONIAN PERIOD. 55 



and Kenmare ; lie thinks the apparent conformity is decep- 

 tive, and that there is everywhere a great break between 

 the GlengarifE series and the Carboniferous beds. It is 

 certainly very difficult to reconcile the Dingle and G-len- 

 gariff sections on any other view, for there is no reason to 

 believe that there are any beds at Grlengariff which are un- 

 represented at Dingle, but rather that there are beds below 

 the Carboniferous shale east of Dingle which are absent in 

 the Glengariff country, so that, as Professor Hull argues, 

 the greater break is actually where there is least actual 

 evidence of it. The G-lengariff grits occupy a large surface 

 area in the south of Kerry, and extend eastward through 

 the central part of Cork. They are believed to underlie 

 the whole of South Cork and the greater part of Kerry, 

 but their northern limit is unknown, and is probably con- 

 cealed under the Carboniferous beds of North Cork and 

 Limerick. 



2. Devonian System. The rocks of this system are only 

 found in the south of England, and they are only exposed 

 to view in the counties of Somerset, Devon, and Cornwall. 



The rocks of North Devon and Somerset are divided into 

 three groups, which, as at present defined, consist respec- 

 tively of the following strata : (1) hard purple and grey 

 grits at the base, with grey slates and thin grits above; 

 (2) sandstones succeeded by a series of thin-bedded lime- 

 stones, grits, and slates above these are thick green and 

 grey slates ; (3) purple slates succeeded by red, brown, and 

 grey sandstones. 



In South Devon and Cornwall the rocks are so contorted 

 and faulted that it is difficult to determine the real se- 

 quence, but it is known that there are (1) red sandstones 

 and slates with Lower Devonian fossils, (2) a great series 

 of slates and limestones (with interbedded volcanic rocks), 

 which represent the Middle Devonian, and (3) a slate and 

 sandstone r group resembling that in North Devon. 



