550 Home — Old Sea-Clifs, etc., of the Firth of Forth. 



Glacial action in the Tay, in tlie upper part of which, about Weem, 

 there are decided moraines. In most of the great outlets from the 

 Alpine regions of Scotland — as, for example, the valleys of the 

 Spey, the Findhorn, and the Ness — there are smaller sheets of 

 gravelly alluvium gathered about the places where the valleys open 

 into the low country. In the case of the alluvial sheet here de- 

 scribed, there has been sufficient denudation and outsweeping to 

 account for the sand-banks which so largely encumber the mouth of 

 the Tay, and give so much trouble to the mariners of Dundee. 



II. — On the Old Sea Cliffs and Submarine Banks of the Fieth 

 OF Forth. By D. Milne Hom?, F.R.S.E., F.G.S. 



IN describing the line of old sea-cliff along both sides of the Firth 

 of Forth, which had been formed before the last change in the 

 relative levels of sea and land, Mr. Home stated that its height at 

 the lower parts of the estuary was about thirteen or fourteen feet 

 above the present level of the sea, whilst near Stirling it was about 

 thirty-one feet, and to the west about thirty-five or forty feet. He 

 also specified two higher and older cliffs at heights of about sixty feet 

 and one hundred and thirty feet respectively. Skeletons of whales 

 and seals had been found at heights varying from eighteen to twenty- 

 three feet above the present level of high-water-mark, and sea shells 

 were found in two conditions — viz., first, in undisturbed beds, now 

 fourteen and fifteen feet above high- water-mark, entire and perfect ; 

 and, secondly, in beaches, where they were broken. He explained 

 the origin of the Estuary of the Firth, by the great east and west 

 fractures in the country adjoining, to the north and south. He said 

 that in the Fife Coal-field, the downcasts were almost all on the 

 south side of the fractures, and amounted altogether to nearly 2,000 

 feet ; and in the Coal-field of the Lothians, Linlithgow, and Stirling- 

 shire, the downcasts were, on the other hand, to the north, and even 

 to a greater extent, thus producing a trough or hollow, now filled 

 by an arm of the sea. The rocks in this hollow were covered by 

 various drift deposits, the oldest being Boulder-clay, and, over it, 

 stratified claj, sand, or gravel. The gravel was generally on the 

 top, which was accounted for by the water of the Estuary shallowing, 

 whereby the currents became more powerful, and thus gravel was 

 laid down where only mud or sand could be laid down before. Mr. 

 M. Home next proceeded to describe a long ridge of gravel running 

 four or five miles through Callendar Park, by Polmont eastward 

 towards Linlithgow. He stated that its height was from thirty to 

 sixty feet, and, judging from the materials composing it, he con- 

 sidered it had been formed by sea-currents. He said that these 

 gravel ridges were very numerous in our open valleys, and that 

 their direction or course was invariably parallel with the axis or 

 sides of the valley. Though he had not seen the ridge of gravel at 

 St. Fort, described in Dr. Chambers's paper, he could not help think- 

 ing it M^as to be accounted for in the same way, viz., by marine 



