300 TrNEDALE ESCAEPMENTS ; 



cut a ledge ui)ou the rock, succeeded by more rapid movement, 

 when they had not even time to obliterate fine glacial scratches.* 

 This view, early taken by Darwin, in the case of step-formed ter- 

 races in South America, receives a measure of confinnation from the 

 old coast lines on our own shores, and is enough to make us chary 

 of any theory based on " gradual and successive uncovering of the 

 land." We look, quite in vain, for coast-terraces, like broad con- 

 tour lines, intersecting the ridges as they descend from the water- 

 shed towards the valleys. The sea, moreover, has nowhere been 

 pointed to as carving out ridges that slope longwise down to its 

 shore : all the lines it engraves are more nearly parallel with its 

 margin. I need scarcely object further, that these ridges, if old 

 sea-work, should give signs of obliteration under the hand of time, 

 or that marine debris and shells might possibly be expected, — 

 arguments not of much value. Lyell, with the fine candour for 

 which he was pre-eminent, frankly gave up this marine theory, 

 long held by him in explanation of the large double ampliitheatre 

 of escarjiments bordering the AVcald. Even its most determined 

 upholder, Mr. Macintosh, who devotes a hundred pages of his 

 book on the Physical Featuies of England to this view, some of 

 them scarcely, I feai*, exemplifying the ''Scientific uses of the 

 Imagination," seems to have slackened in his support of it.f 



In another more limited aspect I shall have occasion to revert 

 to marine action in the sequel. The claims of a geological agent 

 of such fundamental importance demand thorough consideration. 



4. Theory of Glacial Excavation of Escarpments. — Among the 

 denuding forces of nature there is no perfect planing agent. Phillips 



* I have in tniiul more especinlly the fine terrace beneath Stenbjerget, at Tromlhjem. 



t It is far from my intention to deny that inland sea-cliffs may and do exist, and that 

 •ome of the features described l)y Mr. Macintosh may l)C marine. It is enough, however, 

 greatly to impair the value of Mr. Macintosh's researches that ho describes as marine 

 what, as was pointed out at the time by Scrope, seem to l>c merely tlie vestiges of former 

 culture. Such " culture terraces" are not infrequent in North Tynedale, and hare bceu 

 fully desrril^ed in a former volume of these Transactions by my friend the Rev. O. R. 

 Hall, F.8.A. A concluHive summary of the differences between .Se<»-C'liff» and Escarp- 

 ments has been given in parallel columns by Mr. Whitaker (Oeol. Mag., 1867), whoso 

 half-amazed exclamation, •• What can be more different than these two?" well deserTed, 

 when one or two inaccuracies of statement were corrected, to be "the conclusiou of tlie 

 whole matter." 



