TRANSACTIONS OF SECTION C. 481 
genius, Uquus, Cervus megaceros, and Chellean (?) implements), which now fills 
the preglacial channel in the chalk to a proved depth of 170 feet.2 
(2) The Chalky Boulder Clay of the plateau (as distinguished from its 
‘rubble-drift derivatives) is well defined on either side of the upper valley of 
the Stort at altitudes of 240 feet to 270 feet (o.p.), maintaining a pretty con- 
stant character in numerous grave-sections, well-sections, and open excavations. 
Its general facies and composition differentiate it from the Harlow Till, and 
from that which occurs at lower level in the valley, 220 feet to 230 feet (o.D.). 
(3) The Valley Boulder Clay consists at Thorley of a compact silty 
deposit, devoid of chalk detritus, elongated erratics often standing erect in it, 
presumably dropped from stranded ice-rafts. In the Thorley gravel-pit good 
sections (transverse to the valley) have shown some seven feet of such a boulder 
clay intercalated with contorted gravels, including ‘ gravel-boulders’ (Bonney), 
originally deposited as frozen masses, and showing evident causal connection 
with the contortions. The whole deposit overlies the sandy interglacial 
current-bedded gravel (12 feet), with included erratics, seen in greater force 
in the more extensive gravel-pit on the other side of the valley, forming an 
interglacial series younger than the plateau Chalky Boulder Clay but older than 
the contorted gravel series (with intercalated Boulder Clay) of the valley. (See 
section with altitudes determined by ‘levelling,’ fig. 1 of circular of the 
Geologists’ Association for excursion on June 21, 1913.) 
(4) In some recent deep well-sections (piercing the chalk) a distinction can 
be drawn between the Chalky Boulder Clay and the Blue Boulder Clay (=Harlow 
Till) with a zone of ‘rubble’ between them. Horizon of the Latton and 
Hockerill gravels. 
From the above data the following tentative correlation is put forward for 
the consideration of geologists :— 
Peaty Alluvium (post-glacial) of the Stort and the Lea, &c.: finer ‘rubble- 
drift’ of lower valley-flanks. 
(iv) Valley Boulder Clays and Contorted Gravels: coarser ‘rubble-drift’ 
of higher valley-flanks: YH. primigenius and Hquus, paleoliths [Hessle Boulder 
Clay ?] (= ‘Wurm ’* or ‘ Mecklenburgian ’ *). 
[Sands and gravels (in part) of Anker’s and Rippon’s pits, near Peter- 
borough. ] ° 
Third Interglacial : current-bedded fine gravel and sand with erratics. 
[Sand and shingle, with Mammoth, &c., and erratics filling old river-channel 
at Fletton.] ° 
(ili) Chalky Boulder Clay of Hast Anglia: Stortford and Thorley plateau 
{= ‘Riss’ 4 or ‘ Polandian ’®). 
Second Interglacial: glacial shingle filling the older Stort Valley, with 
extinct Pleistocene mammalian remains and very early paleoliths; sand and 
shingle of the Latton pits to the S. of Harlow.’ 
[Interglacial sands of the Gipping Valley.] 
we Harlow Till (=‘ Mindel’4 or Saxonian*); Saffron Walden and Cromer 
tills. 
First Interglacial : (‘Norfolkian’*) not delimitable from (i). 
() Herts Plateau-Drift (= ‘Ginz’* or ‘ Scanian’*) of the Stortford Water- 
works.°® 
The ‘Great Ice Age’ would be represented by (ii) and (iii) in the above 
scheme; its gradual incoming by (i), and its gradual outgoing by (iv). 
B.A. Reports, Portsmouth Meeting (1911), pp. 521-2. 
Photographs (slides) by Mr. H. G. Featherby, of Bishop’s Stortford. 
Penck and Brickner. 
Professor J. Geikie. 
See paper read in Section C last year; printed in extenso in the Geol. Mag. 
for September 1913. 
7 These underlie the Chalky Boulder Clay in the pit-face for some 200 yards, 
and contain many rolled and weathered erratics from the Harlow Till; the 
‘Schotter’ is mainly composed of such material. The extra weathering and 
rounding differentiate them as a series from those found in the Till itself. 
8 See Mem. Geol. Surv. vol. iv., p. 449. 
1913. . II 
on fF Ob 
