Aug. 7, 1873] 
NATURE 
i 
" 
opis 
5, 
287 
THE GLACIAL DRIFTS OF NORTH LONDON 
"TRE landscape memorials of the great glacial period 
4 in Britain have hitherto been chiefly looked for by 
the tourist in the northern and mountainous districts of 
our island. The vast and wide-spreading products of the 
same epoch which lie in the lower and more southerly 
districts of England, as far as the Valley of the Thames, 
have had to wait longer for their due recognition. In the 
interval, the Londoner addicted to geologising has been 
fain to go to Snowdonia, Borrodaile, and the Highlands 
of Scotland—to the region of perched blocks and ter- 
minal moraines—for memorials of the Ice Age within 
our own coasts. Nor is it to be wondered at that the 
districts in which glacial action on a grand and cosmical 
scale was first detected in Britain, and which still afford 
the more obvious monuments of the glacial period, 
should so long have monopolised attention. But the time 
seems now to have come for the drifts of the southern 
regions to take their proper place in the gallery of glacial 
phenomena. 
So recently have these drifts changed their character 
in the eyes of geologists that it may be worth while to 
summarise their history, and indicate the conclusions 
which have now been arrived at with regard to them as 
well as one or two important moot points which will per- 
haps remain doubtful for some time to come. 
It seems only yesterday that the glacial drifts of the 
GLACIAL PLATEAU 
NORTH LONDON, 
AND ITS HYDROGRAPHY: 
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Mill Hitt 
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OF, THE 
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oR EXER 
he ae Z 
Sas ee 
Rx SX xx 
East Barnet 
SSS 
to Enfield 
ie 
S scuthgate 
Colney Hatch 
Lunatic Asyluny 
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Lig rnsey 
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\ Fast Lah 
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ee 
Dds Crovch Ena* 
Bishops Wood a Q 
Fic. 1.—A, Glacial Sands and Grayels, B, Glacial Clay. Unshaded Parts—London Clay. 
lower and southern districts of England were looked upon 
as a mere congeries of rubbish heaps and “ diluvium ”— 
chaotic and unintelligible relics of some mysterious and 
partly hypothetical period. Now, however, these deposits 
are no longer slighted by geologists. In the hands of one 
or two earnest workers—notably Mr. Searles V. Wood, 
jun.—the glacial clays, and sands, and gravels of England 
are rising into the dignity of a system. The North Lon- 
don glacial drifts may be taken as typical in most respects 
of the great and wide-spreading deposits which are found 
in the inland counties most remote from the homes of the 
old British glaciers. - 
The Finchley and Muswell Hill drift lying on the north- 
ern heights of London overlooking the Thames Valley 
occupies a position of great geological interest and signi- 
ficance. Muswell Hill figures in the very early annals of 
the beds which are known to be of glacial origin. In 
the year 1835, Mr. N. T. Wetherell, of Highgate, 
made the discovery which has given such repute to 
the spot. In Coldfall Wood, just beneath the vegetable 
soil, Mr. Wetherell found one of those strange medleys 
which geologists were then wont to dismiss as “diluvium.” 
Here, as far south as the Thames Valley, were water- 
worn fragments of granite, mountain limestone, coal, red 
chalk—indeed rock-specimens from all the northern 
formations, with a similarly heterogeneous collection of 
