i 
HARMER : FIELD EXCURSION TO CROMER, ETC. 
At Pakefield this deposit, 
which there rests on the Middle 
Glacial sand, is of a dark indigo 
colour, and of a tough, sticky- 
character, and is composed to 
a large extent of Kiineridge Clay 
material. The hard chalk and 
grey flint of the Wolds are very 
common in it, and in this district 
Xeocomian detritus is not rare ; 
a few boulders of dolerite or 
diabase were noticed here, and 
one of porphyrite. 
A great part of the area 
included in Sheets 50 and 66 
(see Fig. 4) is covered by boulder- 
clay resembling in every respect 
that of- Pakefield ; see, for 
example, PI. XLVII., copied from 
a photograph of a railway cutting 
near Forncett Station, more than 
20 miles to the west of the former 
place, which was visited on the 
following day. This immense 
sheet of homogeneous material, 
always more or less Kimeridgian, 
and sometimes nearly 100 feet in 
thickness, which covers more than 
1,000 square miles of countrj^ 
seems to the writer to have been 
due, as stated in the paper read at 
Cromer, to an ice stream from the 
Fens, which to some extent ex- 
cavated, or at least deepened the 
gap in the Chalk escarpment 
between Swaffham and Xew^- 
market, pouring in great volume 
through it, and along the low 
311 
