Vol. 57.] ORIGIN OF THE DUNMAIL RAISE. 193 



main Yalley in what would be the normal direction for a southward- 

 flowing river. 



There remains the consideration of how the explanation of the 

 origin of the Dunmail Raise offered above affects, or is affected by, 

 the accepted ideas regarding the elevation of the mountain-mass 

 which it traverses. Since the time of Hopkins's paper,^ it has 

 been recognized that the elevation to which these mountains owe 

 their present existence is of much later date than the principal 

 disturbance of the rocks composing them. In the paper just quoted, 

 the axis of elevation is regarded as a linear one, the elevation 

 attaining its maximum to the westward, in the neighbourhood of 

 the Sea JFell Pikes, and lessening to the eastward. In more recent 

 5'ears the concept of a radially arranged drainage, originally due to 

 the poet Wordsworth, has been taken into scientific literature ; and 

 in a geographical paper published by Dr. H. R. Mill in 1895,^ the 

 symmetry of the mountains is regarded as radial, not linear. He 

 considers the mountains as carved out of a dome, traversed from 

 north to south by two long depressions: — that of Thirlmere, 

 Dunmail Raise, and Windermere, and that of Borrowdale, Stake 

 Pass, and Conistone ; and he illustrates his paper by a skeleton-map 

 of the district, on which a series of circles are drawn round a centre 

 on High Raise, midway between the Dunmail Raise and Stake 

 Pass. On this map the lakes and principal valleys are shown to 

 converge towards this assumed centre of elevation. In 1889 ^ 

 Mr. J. E. Marr had propounded the same view, and published a 

 skeleton-map, very similar to that of Dr. Mill but without the 

 concentric circles, and with geological indications showing that 

 the present centre of maximum elevation is widely different from 

 the axis of disturbance of the Palaeozoic rocks. He considers that 

 the only agency which could produce a dome-shaped uplift of the 

 form postulated was the intrusion of a laccolite. 



In the maps referred to, only the present lakes and river-courses 

 are shown, and in them an appearance of radial symmetry can be 

 easily detected, which disappears if the old Dunmail River is 

 restored,^ and also if a relief map of the district is examined. 

 On a map of this character, it is seen that the mountain-mass is 



1 Quart. Journ. Greol. Soc. vol. iv (1848) p. 70. 



- Geogr. Journ. vol. vi (189.5) p. 46. 



3 Geol. Mag. 1889, pp. 150-55 ; see also Geogr. Journ. vol. vii (1896) p. 602. 



^ It is doubtful whether the Dunmail Kaise is the only trace left of an older, 

 now vanisliecl, drainage. The Kirkstone Pass has much the appearance of a 

 valley brheaded by the Stock Gill cutting back from the south, but the resem- 

 blance i.s not complete. The ascent of the valley, which drains northward, is 

 not continuous to the summit, towards which it flattens off, and there is a 

 slight descent, before the rapid drop into the valley of the Stock Gill is reached. 

 This may be entirely due to the accumulations of morainic material ou the 

 summit f but it seems probable that the Kirkstone Pass had once the sameform, 

 and was originally due to the same cause, as the Dunmail Raise, and that the 

 cutting back of the Stock Gill has been the cause not of the gap itself, but only 

 of a modification in its form. If this be so, the Kirkstone Pass marks the valley 

 of an old river, which formerly flowed from the north through Ullswater to the 



