David Milne, Esq., on Polished and Strmted Rocks, 167 



great force and power, is manifest from the enormous size of some of 

 these boulders. 



I am aware that some glaciallsts have ventured to explain the 

 transportation of boulders, even in the situation of those now referred 

 to, by imagining that they were transported on ice-floes, and dropped 

 on the places where they are now found. Mr Maclaren mentions 

 several facts inconsistent with this theory as applicable to Arthur 

 Seat. He states that some of the boulders are of sandstone, and on 

 places " 400 feet above any spot where sandstone now exists in situ.''* 

 l3ut if the parent rock was below the level of these boulders, how 

 could they have been floated from it to their present position \ He 

 states, also, that the accumulations of boulders are almost always on 

 the east side of prominences, leading to the conviction, that they had 

 been hurried along by a rush of waters from the westward, and de- 

 posited on the lee- sides of these prominences. 



The occurrence of limestones, sandstones, shale, and coal, in the 

 boulder-clay of the gully at Sampson's Ribs, is equally adverse to 

 the theory of flotation by ice-rafts. Wherever these blocks have 

 come from, they must have been brought from parent rocks, situated 

 below the level of Sampson's Bibs. Eurdiehouse, Kirkliston, Mid-Cal- 

 der, Queensferry, and Newbigging in Fife, are the only places where 

 the limestone with Entomostraca is known, and they are all of them 

 at a lower level. Gilmerton, which is the nearest point at which 

 marine limestone is worked, is still lower, and so also are the other 

 more distant localities from which it probably came, viz., Linlithgow, 

 Charleston, and Invertiel in Fife. The coal-sandstone and coal, 

 being exceedingly friable, could not have been brought from a great 

 distance ; and there is no place in the neighbourhood from which 

 these blocks could have come, which is not, at least, 200 feet below 

 the level of Sampson's Ribs. 



But these boulders, if they had been dropped from floating ice- 

 bergs, would not have been imbedded in the extraordinary deposit 

 characterised by them. If it was the bottom of the sea upon which 

 they fell, one would expect to find them lying on beds of sand or 

 nmd ; whereas they are generally enveloped in a tenaceous clay, in 

 some places 100 feet deep, — as at Leith. Was this clay also trans- 

 ported and dropped by individual icebergs *? If so, would it form, 

 as it does, a continuous deposit over the whole of the Scottish Low- 

 lands ? Would it not rather have occurred only in small patches, and 

 presenting some traces of stratification \ 



The same agent which brought the boulders, must have brought 

 the clay in which they occur ; and, spread as it is over the whole of 

 the country south of the Grampians, there must have been one agent, 

 which transported and spread it, — not separate icebergs floating here 

 and there. 



(2.) The next point, is at what period this debacle of water took 

 place] 



