THE AGE OF THE LAST UPRISE OP THE BRITISH ISLES. 185 



This wall was constructed to repel the attacks of the Caledonian 

 tribes from the north, and was abandoned about 45 years after- 

 wards, which would bring us down to about A.D. 187, or the 

 close of the second century of our era. 



Dealing; with the eastern end of the northern wall. Sir 

 A. Geikie states that west of Borrowstounness (or Bo'ness), the 

 ground rises from the old coast line as a steep bank the summit 

 of which is 50 to 100 feet above the sea. Between the bottom 

 of this abrupt declivity and the present margin of the Firth of 

 Forth there is a narrow strip of fiat ground on which Bo'ness is 

 built, and which nowhere rises more than 20 feet above high- 

 water. It is in fact a prolongation of the Carse of Falkirk and 

 of the raised beach of central Scotland, w^hich was submerged 

 when the waves beat against the steep bank which here formed 

 the old coast margin. But the important point for us is, that the 

 Eoman wall appears to have terminated at the top of the steep 

 declivity. The flat terrace below, over which, if it had been 

 land as at the present time, the rampart would have naturally 

 been carried to the sea margin, presents no traces of this " wall 

 or foss." In the words of Sir A. Geikie, " if the land were here 

 depressed 25 feet, no part of the wall would be submerged."* 

 Again, the western extremity of the wall stood on a little 

 eminence called Chapel Hill on the north bank of the Clyde 

 near West Kilpatrick, and the conditions are somewhat similar 

 to those of the east end of the wall. Between the rising 

 ground and the margin of the river is the nearly flat terrace 

 about 20 feet above high- water mark, and tlie base of the hill is 

 5 to 6 feet higher ; over this terrace the wall does not appear to 

 have been carried, and it is now traversed by a railway and canal. 

 In making the latter a number of Koman antiquities were found : 

 the terrace is a portion of the raised sea beach. The inference 

 seems clear that the vallum, terminated at the promontory of 

 Chapel Hill, because at the foot of the descent the sea itself 

 formed a sufficient protection against the Caledonian high- 

 landers as far at least as an advance by land was concerned, 

 and the same remark applies to the eastern extremity at 

 Bo'ness. The strategetic reasons for terminating the walls are 

 self-evident on the hypothesis that they were carried from sea 

 to sea. To leave wide spaces at either end incomplete while the 

 rampart was carried over the intervening land would have been 

 an act of folly for which we cannot credit such skilful 

 engineers as were the Eoman settlers. Hence in the words of 



* Ihid., p. 230. 



