l.*4 The Rev. Maxwell H. Close, 



vicinity. It is perfectly certain that it must have been the rock- 

 scoring agent which produced the boulder-clay ridges. Having 

 ascertained this, we can often recognise the course of the flows of 

 the universal ice-sheet by the mere inspection of an accurately 

 shaded map. See the shaded Ordnance inch maps, Nos. 100, 

 101, 110, and 111. These drumlins are even more strikingly 

 displayed in other parts of Ireland. 



The rock-scorings and these ridges show that the great glacial 

 flow from the north-westward was divided not far from 

 Maynooth, evidently by the obstruction of the Dublin and 

 Wicklow Hills ; see the glacial map of Ireland in Prof. Hull's 

 Physical Geology and Geography of Ireland, p. 210. Agassiz, 

 when in Dublin in 1840, having seen but little of the glacial 

 phenomena of the neighbourhood, naturally supposed that those 

 hills must have been a centre of glacial dispersion. But it is 

 very interesting and remarkable to find that they were not so, 

 but that they were invaded ah extra by a great ice-flow which 

 can be traced backward to the less important hills of Fermanagh. 

 They had, however, afterwards, their own small local glaciers as 

 we shall see presently. 



Stratified Drift. — Immediately over the Lower Boulder clay, 

 which was clearly the moraine da fond of the great ice- flow 

 from the north- westward, comes a deposit of stratified water- 

 arranged and washed gravels and sands. These, which we shall 

 call the Middle Sands and Gravels, extend from the present sea 

 level up to a considerable elevation on the hills. They reach 

 1, 100 feet on the S.E. side of the Three Bock Mountain, 1,300 

 feet on the W. side of that hill, on the summit of the col connect- 

 ing it with Kilmashogue Mountain, 1,250 feet at 2\ miles W. 

 by S. of the last, and the same elevation at one mile W. of this 

 last on the eastern side of Mount Pelier. The distance between 

 the first and the last mentioned spots is five miles. 



These elevated parts of the gravels and sands are as well 

 washed and sorted as those on the low grounds ; they moreover 

 consist as largely of foreign materials ; although resting at those 

 heights on granite hills they are part of the " limestone gravel." 

 Pieces of flinty chalk and other far-transported stones and 

 fragments of marine shells can be found in them as in the low- 

 lying gravels. The shells found in the gravels of this neighbour- 



