194 NEOZOIC TIME. [CHAP. X. 



removed since the Cretaceous period, there is very little of 

 the territory which, with the addition of this thickness 

 (viz., 1,000 feet on the mountains), would overtop a line 

 drawn 3,900 feet above the present sea-level. From this 

 rough calculation, therefore, we may infer that if any land 

 rose above the waves of the Upper Chalk sea on the site of 

 modern Wales, it merely consisted of a small area overlying 

 the present Snowdonian range. 



The islands of the Irish archipelago were reduced to 

 smaller and smaller dimensions, and it is probable that 

 chalk once covered the greater part of the country, but 

 whether the whole of it was ever submerged we have no 

 means of ascertaining ; and the same may be said of the 

 south of Scotland. With regard to the Highlands, from 

 the position of the Chalk in Morvern, and from the beds of 

 flints associated with the Tertiary lavas, we may infer that 

 it originally covered all the lower parts of Argyle and 

 Inverness. Flints abound, and fragments of chalk are 

 not uncommon in the Glacial deposits of the eastern coast, 

 proving that " the Chalk must once have been in place at 

 no great distance, if, indeed, it did not actually cover part 

 of Aberdeenshire and the neighbouring counties." ] We 

 shall not, therefore, be assuming more than the facts war- 

 rant if we conclude that the central Highlands formed an 

 island in the sea of the Upper Chalk. 



How far this sea extended northward it is hard to 

 guess, but some speculations have been hazarded even on 

 this point. It is certain that the greater part of western 

 and southern Europe was covered by an ocean which 

 seems to have had a wide latitudinal extension, and may 

 have been continuous from the southern part of North 

 America, across the Atlantic, and through Europe into 

 Asia. If this was the general trend and extent of the 

 Cretaceous ocean, we may reasonably suppose the larger 

 1 A. Geikie, l: Scenery of Scotland," 1887, p. 125. 



