450 D. MACKINTOSH ON THE ERRATIC BLOCKS OF 
2. Along the Coast of the Irish Sea &c.—Assuming the terrestrial 
origin of the blue clay with local boulders which extends from the 
neighbourhood of Keswick to the Irish Sea (under all the other drift- 
deposits), and reappears on the coast of North Wales, and correlating 
this blue clay with the lowest or “‘ waxy” pinnel of the southern part 
of the Lake-district, there would still be an extensive heterogeneous 
deposit of argillaceous, gravelly, and sandy pinnel in and around the 
borders of the Lake- district ; and this, along the shores of Morecambe 
Bay, may be traced graduating into the Lower Boulder-clay of the 
plain of Lancashire and Cheshire. ‘The lower part of the clay-cliffs 
between Bardsea and Baycliff (near Ulverston) are evidently on the 
same horizon as the lower part of the clay-clifts at Blackpool, while 
the latter is a perfect facsimile of the lower part of the clay-cliffs at 
Dawpool, Cheshire (see II. $5). All along the east coast of the Irish 
Sea the boulders are most numerous towards the base, or in the 
loamy part of the Lower Boulder-clay. This would seem to indicate 
that there must have been a depth of water sufficient to enable the 
boulder-laden floating ice to clear the minor eminences before much 
of the lower clay was deposited. The far-transported boulders, such 
as the Criffel granites around Wolverhampton, differ to a considerable 
extent from those found at Dawpool, so as to indicate deeper water 
when they were transported. If so, the Boulder-clay and equivalent 
gravel and sand around Wolverhampton may represent the upper 
part of the Boulder-clay of the basin of the Irish Sea. 
3. In the Plain of Cheshire, Shropshire, fe.—The Upper Boulder- 
clay of this plain is very extensively distributed, but (as long ago 
noticed by Prof. Hull) the Lower Boulder-clay is seldom seen south 
of Chester. It may exist in many abrupt hollows under the great pall 
of Upper Boulder-clay ; but, so far as it can be detected, it gradually 
degenerates southward until in many places it is only represented by 
boulder-gravel, earth, sand, or loam (as may be seen at the bottom 
of Gresford valley, at low levels around Shrewsbury, &c.). This 
degeneration is evidently owing to a southerly diminution in the 
supply of the subglacial mud from the Lake-district. It may, how- 
ever, at first have been more or less present in Shropshire, and used 
up or carried far away during the accumulation of the cleanly- 
washed middle gravel- and sand-deposit, which, to a considerable 
extent, consists of erratics which must have been transported during 
the Lower Boulder-clay period. Up the hill-sides the Lower Boulder- 
clay degenerates much in the same way as it does southwards, as if 
the deposition of the clayey matrix had chiefly taken place in the 
deepest parts of the gradually deepening sea. 
4, Around Wolverhampton, Stafford, §c.—The great plain of 
Lancashire, Cheshire, Shropshire, and part of Denbighshire (in other 
words, the plain lying between the Pennine hills and the Welsh 
mountains) is separated from the midland area by a waterparting 
(which is only breached by the river Severn) extending from the 
neighbourhood of Church Stretton, by way of the Wrekin, Ashley 
Heath, and Mow Cop, to the Pennine hills. South, south-east, and 
east of this waterparting the lowest of the two clays of the north- 
