Vol. 70.] GLACIAL GEOLOG-Y OF EAST LANCASHIRE. 205 



on the lower ground south-east of the hill. Good sections in the 

 North- Western Drift occur on the northern, and in Ribblesdale 

 Drift on the southern, slopes of the ridge east of Great Hameldon 

 almost up to its crest, which, for about a mile, clearly marks the 

 boundary between the two types. Farther east, the limit of the 

 North- Western Drift falls until reaching the gap at the head of 

 the Limy- Water valley, through which it passes. Small boulders 

 of igneous rocks are found sparingly among the Drift in the upper 

 part of the Limy- Water valley up to about 925 feet, above which 

 Bibblesdale Drift only occurs. 



Along the hillside south of Burnley, Lake - District rocks are 

 quite abundant near the limit of their distribution, which falls 

 gradually eastwards and then rapidly south-eastwards towards the 

 entrance to the Cliviger gorge. A clear boundary has been traced 

 along the western slopes of the Pennines south-east and east of 

 Burnley, at altitudes up to 1050 feet O.D. ; other records l serve 

 to continue it north-eastwards, until it crosses the Pennines into 

 Airedale. 



(2) From Great Hameldon to the Walsden gorge. — 

 Immediately south of Great Hameldon, the Drift includes a few 

 scattered boulders of Lake District rocks, which for nearly 2 miles 

 are found only on the west of the ridge from Great Hameldon to 

 Cribden, the ridge itself and its eastern slopes being covered by 

 Bibblesdale Drift. Farther south igneous rocks are found across the 

 ridge, and become increasingly numerous along it — many occurring 

 around Cribden, 2 and a few on its summit (1317 feet above O.D.). 



South of Cribden the Irwell Valley extends eastwards towards 

 Bacup, and the North- Western Drift is abundant 3 all the way, 

 rising to high altitudes on the north, east, and south of the 

 Rossendale basin. On the ridge east of the Limy- Water valley, it 

 reaches a northern limit at 1075 feet above O.D., towards which the 

 Lake-District boulders diminish in number and in size. Farther 

 north this ridge is scantily covered by Bibblesdale Drift. 



Southrwest of the high ground east of the White well-Brook 

 valley, the North- Western Drift does not extend so far northwards, 

 nor does it attain so great an altitude as farther east on the hill- 

 slopes around Bacup. Moreover, from this point, the Bibblesdale 

 and North-Western Drifts are no longer in contact, the latter 

 extending beyond the area occupied by the former, and passing at 

 high levels into Local Drift. 



1 A. Wilmore, Trans. Burnley Lit. & Sci. Soc. vol. xv (pub. 1900) p. 58 ; id. 

 'Glacial Geology of Colne & District ' Proc. Colne Lit. Sci. Soc. 1908, p. 17 ; 

 and A. Jowett & H. B. Maufe, Proc. Yorks. Geol. Soc. n.s. vol. xv (1904-1905) 

 p. 200. 



2 J. Aitken, ' On the Occurrence of High-Level Drift in the Neighbourhood 

 of Bacup ' Trans. Manch. Geol. Soc. vol. xiii (1874-76) p. 137. 



3 J. Aitken, Trans. Manch. Geol. Soc. vol. xiii (1874-76) pp. 134, 137 ; 

 J. Kerr, ibid. vol. x (1870-71) p. 117 ; H. Bolton, ' Geology of Rossendale ' 

 1890, pp. 139-52 ; and id., ' On the Finding of Marine Shells in the Boulder 

 Clay of Bacup ' Trans. Manch. Geol. Soc. vol. xxi (1892) p. 574. 



