16 PROFESSOR P. F. KENDALL AND MR E. B. BAILEY 



northern and eastern Hanks of the Lammermuirs. passing by Tynehead in the west and 

 Oldhamstocks in the east. Between these two villages the continuity of the terrace 

 was broken by two important spurs, namely, Deuchrie Dod and Cocklaw Hill. Behind 

 each of these at one time or another important lakes were doubtless imprisoned, and 

 it seems probable, from the nature of the deposits in the Upper Keith district, that 

 Deuchrie Dod served temporarily as the eastern limit of a narrow marginal lake fully 

 fourteen miles in length. But the history of this terrace was long and varied ; we 

 shall presently have to deal with evidences to show that the ice in front of which it 

 formed was frequently oscillating to and fro. In fact, it marks much the most important 

 halt, if such a name may be applied to a limited though restless wandering to and fro, 

 which occurred during the retreat of the ice sheet from East Lothian. Thus it came 

 about that the marginal drainage system of this zone reached a mature development 

 along the lines indicated above. At first almost the whole extent of the marginal area 

 was loaded with sediment, though, of course, the supply varied greatly in amount and 

 from place to place ; erosion occurred only across the two spurs already mentioned until 

 the general lowering of the base level caused the emergence of minor ridges and the other 

 consequences which we have indicated above. But before the ice sheet had finally 

 retired, the terrace so formed had been dissected from end to end by marginal streams 

 and the work of its demolition had already far advanced. 



Above and below the limits of this great terrace we may recognise others, but never 

 on the same grand scale. A well-marked higher terrace may be referred to leading 

 eastwards from White Castle towards Deuchrie Dod. Its level is approximately 800 

 feet above the sea. 



We shall now consider the other great zone of deposit, that of the coastal spread. 

 At Oldhamstocks it comes into contact with the great Lammermuir terrace, but it is 

 obvious in the field that the deposits of this locality have an extremely complex history, 

 and that those occurring at hio;h levels were formed at a time when the ice sheet must 

 have blocked all direct egress to the sea. The whole coastal spread is, in fact, built 

 up on this plan, and it owes its continuity to the juxtaposition and overlap of deposits 

 formed successively and not contemporaneously. It cannot therefore be regarded as 

 an entity, even in the same extended sense in which that term might be used to describe 

 the complex Lammermuir terrace. It is merely the gravel spread which formed where 

 the mouths of the glacial drainage channels debouched upon the coastal plain, and as 

 these came into being in succession from south-east to north-west, following the retreat 

 of the ice sheet, it is obvious that the coastal gravels near Oldhamstocks, for instance, 

 were formed at a considerably earlier date than those about the mouth of the Tyne. 



