304 D. Mackintosh — The Drifts of the Lake District. 



(as is evidenced on the coast at Parkgate) others, up to a great 

 diameter, may have been shifted horizontally. Some of the scars 

 exist where the Boulder-clay would appear to have risen up into 

 ridges or mounds, as no clay is now found opposite to them at the 

 base of the sea-cliff. Others are clay and boulder plateaux, visibly 

 connected with the cliff-line. Most of the scars, I believe, are 

 remnants of the great Lower Brown Boulder-clay. The most con- 

 spicuous boulder in the scars S.W. of Bootle, is Eskdale-fell granite, 

 accompanied by a little Criffell granite, and a great number of the 

 usual felspathic erratics. 



Drifts near Silecroft and Holborn Hill. — The Eskdale granitic 

 drift near Silecroft suddenly bends round and runs up Whicham 

 valley for some distance E. of the Parsonage. The S.W. end of 

 Millom Hill (which chiefly consists of cleaved felspathic ashes, 

 granular felstone and porphyry), presents the appearance of a 

 beach strewn with many pebbles of granite and other rocks. Here 

 I saw a roche moutonnee with its glaciated side towards the hill, but 

 not in the line of any valley. On the adjacent plain there is much 

 granitic drift. Its inland boundary bends eastwards to the N. of 

 Holborn Hill, crosses the Duddon estuary, and re-appears on Dunner- 

 bolme Island, and near Soutergate. The boundary then runs S.S.E. 

 by Great Urswick, a little N. of which I found a granitic boulder.^ 

 Pebbles of it (probably washed northwards along the sea-coast from 

 its original boundary S. of Baycliff) may be seen near Bardsea. 

 Between Millom Station and Millom Hill, the Upper Boulder-clay 

 knolls apparently alternate horizontally with sand and gravel knolls, 

 but the few sections visible justify the supposition that the two 

 drifts thin out below or above one another in a manner indicating 

 distinct periods of deposition. Between Millom Station and Sile- 

 croft, a similar dovetailing of drift-knolls may be recognized, and in 

 one part of the railway-cutting the sand is interstratified with 

 subordinate beds of clay, but not Boulder-clay. 



Striated Limestone crossed by Drift-carriage. — About half-a-mile S. 

 of Millom Station, a gently-swelling eminence, 75 feet above the 

 sea, has lately been quarried, and the result has been the exposure of 

 the most thoroughly, continuously, and extensively glaciated rock- 

 surface I have yet anywhere seen (Nov., 1870). The grey limestone 

 has been uniformly planed down, polished, and traversed by white 

 grooves and strige. The finer lines have been cleanly cut, but in 

 many places the coarser striae and grooves (the latter about ^th 

 of an inch in breadth) consist of a close succession of rough dints, 

 as if small, sharp, angular quartz fragments had been made to roll 

 over, or as if the floating ice which held the fragments had vibrated 

 after suddenly grounding (?). One might suppose that the polishing 

 of the rock and the microscopic lines were produced by land-ice, 

 were it not that the latter cross each other at nearly all angles. 



1 The boundary in Furness, and in many places further North and South, must 

 have been more or less deeply submerged, and one cannot long trace drift-boundaries 

 without having to abandon the notion that they must always have been marked by 

 dry land, or that dry land necessarily existed where there are driftless areas. 



