492 MR. P. F. KENDALL ON A SYSTEM OF [Aug. 1902, 
withstand much rough usage in transport. This may be termed 
‘the Northern Group. 
Series VI, VII, & VIII, constitute a natural Eastern Group. 
The Jurassic rocks and Cleveland Dyke are native to the Cleveland 
Hills. Mr. Barrow has noted several cases, in which large masses 
of Lias have been lifted and deposited at a higher level than the 
adjacent outcrops. 
Reference has already been made to the relative distribution in 
altitude of the different members of the Drift Series. I may now 
briefly describe the distribution of the Drift as a whole. 
The Drift-deposits, including in the term all deposits of Glacial 
age without reference to the mode of their formation, completely 
surround the Cleveland area, and extend through the two valleys, the 
Vale of Pickering and Eskdale, which run in a westerly to easterly 
direction across the Jurassic outcrop; but, except on the north, they 
extend only a short distance into the hill-country, and the great 
valleys which trench the Jurassic dome on the south side of the 
watershed, as well as the dome itself, are entirely Driftless. 
Regarding the northern slopes of the Cleveland area, Mr. Barrow 
remarks, ‘The Drift becomes very thin at 600 feet above sea-level, 
and disappears altogether above 850 feet.’ My own observations 1n 
the main confirm those of Mr. Barrow, but as, throughout this work, 
I have freely used a hand boring-tackle, I have in a few instances 
been able to rectify his lines in unimportant details of boundaries. 
Commencing at the western end of the great Cleveland escarp- 
ment above Ingleby Arnecliff, the Drift is found to run up the slopes 
to an altitude of about 400 feet; and, though this appears to be the 
general level to which the continuous sheet of Drift attains along 
the steep face of the escarpment, in embayments, such as Scugdale, 
it extends to over 700 feet, and on a few spurs, as at Busby Wood, 
to over 800 feet, and a similar elevation is reached near the ascent 
to Chap Gate. Beyond this point the levels fluctuate considerably, 
and the maximum is attained on the Lockwood Hills, where a 
spread of gravel forms a capping at 867 feet. Farther eastward, 
the boundary varies slightly above and below 800 feet, until at 
Robin Hood’s Butt the watershed falls at one col to the Drift-level, 
760 feet. From Stonegate eastward, the Drift crosses the 
watershed in an almost continuous sheet as far as Whitby, inter- 
rupted however by Kempston Rigg, which forms a narrow Driftless 
strip at altitudes above 800 feet. 
While the actual Drift-deposits are thus limited to levels not 
exceeding 867 feet, there is a sporadic scattering of small erratics 
reaching at three or four places upon the brow of the escarpment to 
higher levels: thus at Carlton Bank, pebbles of foreign rocks were 
found up to 1000 feet. Similar phenomena have been observed in 
other parts of the district : for example, scattered pebbles, mainly of 
white quartz, were noticed by the officers of the Geological Survey 
1 Mem. Geol. Surv. ‘ North Cleveland’ 1888, p. We 
a 
