The Scottish Naturalist. 



is found at Puggiston and Dryleys Tile Works, and in borings on 

 the west side of Montrose. Though I infer from boring notes 

 that this deposit overlies the Boulder clay, I have never actually 

 seen the two in contact. The evidence, however, that the marine 

 clay was deposited in a glacial sea is incontestable, for it contains 

 shells, starfishes, foraminifera, bones of a seal, birds and fishes of 

 a distinctly arctic type. Stones are also found in it of rocks 

 entirely foreign to our district, such as pieces of chalk, flint, 

 sulphuret of iron, coal and bituminous shale. These stones are 

 mostly ice-worn, and had doubtless been dropped to their present 

 position by icebergs from a distant land. 



When the land began to rise again, and the temperature to in- 

 crease, there was what we may term a. period of denudation of the 

 Boulder clay. The gradual melting of the land-ice produced a large 

 lake in the Valley of Strathmore and the Howe of the Mearns, 

 in and around which are deposited the shingle and gravel derived 

 from the higher levels. In course of time the great lake flowed 

 over its barriers at their lowest points, viz., the present river 

 valleys, which were blocked up with Boulder clay. These valleys 

 have been worn down to their present level by slow degrees, leav- 

 ing various gravel terraces, indicating the gradual lowering of the 

 post-glacial floods. The finer sand and mud at the early period 

 would be carried out to sea, while the heavier stones w T ashed out 

 of the Boulder clay would be stranded at the contact of the flood 

 with the sea, forming gradually a storm -beach across the estuary of 

 the South Esk. This great storm-beach or bar of boulders forms the 

 ridge or back-bone of Montrose. Along it stretch the High Street, 

 Murray Street, and the Mall, and it tapers oft on the Marykirk 

 Road at Charleton. On the east side, or sand half, of this ridge 

 stretch the Links seaward, while on the west side, or clay half, are 

 various deposits which indicate changes of climate and level. The 

 denudation of the Boulder-clay in the valleys where it was sub- 

 jected to the full force of the straight outward flood was complete ; 

 but in the low ground, between the estuaries of the North and 

 South Esks, where only eddies and cross currents acted on it, 

 considerable masses were left on the subjacent rock, as at the Nab 

 of Kinnaber and the round hillocks on the farm of Charleton. 



At the close of this Boulder-clay denudation a period of 

 higher temperature seems to have set in ; for in the South Esk 

 estuary we find above the glacial marine clay a deposit of peat, 



