SOUTH-WEST IRELAND. 185 



valley, the land has been relatively 350 feet lower than 

 at present. This is proved by gravel terraces, raised 

 beaches, and shelves cut in the hill-sides, sometimes 

 rock, sometimes glacial-drift, not only in this valley, 

 but in the different adjoining ones. In this valley the 

 altitude of the gravel terraces is about 350 feet, 

 south of Derrinkee Bridge, about nine miles N.E. of 

 the eastern termination of the present sea bay. The 

 accompanying sketch is by our colleague, Mr J. 

 Nolan. In Glenanane, and north of Tawnyard 

 Lough, which lie respectively south and north of the 

 valley, a little above the end of Killary Harbour, 

 there are shelves or terraces at a height of about 350 

 feet ; in an arm from the tributary valley of Fin 

 Lough there is a flat, in Maura valley terraces, while 

 elsewhere the traces of shelves can be detected at 

 similar heights. There are, however, other terraces 

 much better developed and marked than those enu- 

 merated, which can be traced from Derrinkee to 

 Glenanane, having a regular fall from 350 feet to 

 175 feet in a distance of about eight miles. On 

 account of this slope, it might be said that they 

 must be river gravel. This, however, appears to 

 us to be impossible, as during the "Esker-sea" 

 period, when these gravels must have been formed, 

 the whole of the central plain of Ireland, and the 

 valleys in the neighbouring hills, were under the sea 

 which reduced the present mountain-tops to islands. 



