Henry II. Howorth — Geology of the Isle of Han. 457 
as my friend Mr. Binney calls it ; and lastly, we bave beds evidently 
contemporaneous witb and made under precisely the same conditions 
as the Boulder-clay proper, composed of a kind of soft pudding-stone, 
of boulders imbedded in a matrix not of clay, but of disintegrated 
limestone. 
The proportion of lime from the clay in various parts of the 
island is given by Mr. Cumming in Appendix I. of his work, and 
fully confirms this argument, and, as that author says, “ indicate 
the extremely local character of the contents of a great part of the 
Boulder-clay.” (Ibid. p. 306.) 
Let us novv turn once more to the red conglomerate. Superfi- 
cially it will be conceded by those who see it that it resembles an 
indurated Boulder-clay forination of a red colour. This was, in fact, 
remarked by Mr. Cumming, who says of it at one place, “It looks 
extremely like a Consolidated ancient Boulder-clay formation, only 
there is more approach to regulär bedding, more regularity of strati- 
fication, as in the drift-gravel deposits.” (op. cit. 8-9.) The word 
“ ancient” in this extract must be accepted as covering Mr. Cumming’ s 
theory in regard to the deposit ; while as to the regularity of the 
layers of boulders, this is, I talce it, in a great measure imaginary. 
I noticed no such peculiarity except in very local instances. The 
red colour I have already explained as resulting from the formation 
being made up of disintegrated local rocks of an ochreous colour. 
Where the schists and limestones are not purple, the conglomerate 
exists without its red colour, and I have specimens by me showing 
the gradation from a perfectly grey pudding-stone of limestone to 
one quite russet in colour. The inclosed blocks, as I said in my 
former paper, consist for the most part of boulders of the adjoining 
limestone, many with their edges hardly rubbed at all ; and the 
whole deposit, but for its colour and tenacity, is very like the mass 
of undoubted Boulder-clay forming Hango Hill, in the centre of the 
Bay of Castletown. 
The Situation of the conglomerate is also that of a drift deposit. 
It caps the hills and higher ground, as at the Brough and at Langness 
Point, and at the latter place may be studied in close proximity 
to similar deposits without the red colour, which have been de- 
scribed by Mr. Cumming as Boulder-clay. In every sense I believe 
therefore the red conglomerate to be a glacial deposit, and in no 
sense a Devonian one ; and as such a striking example of the law 
prevailing among the glacial deposits of the island in “ changing in 
composition and tallying in Chemical character as well as in litho- 
logical appeai'ance and colour with that of the adjacent rock.” 
(Cumming, op. cit. p. 113.) 
I have not yet referred to what seems to me the most important 
result of this rectification, and which indeed induced me to pro- 
secute my inquiry. I have said that the conglomerate differs from 
an ordinary Boulder-clay deposit in one important respect, namely, 
in its compactness and solidity. This quality it shares with much 
of the grey couglomerate with which I have compared it. The 
cause of this density we must now inquire into. One hom of Castle- 
