IN NORTH HERTFORDSHIRE, 
41 
A few brown, rolled gravel-flint pebbles, the largest 2ins. to 
Sins, long, but generally smaller, also occur. 
A small section near Newnham (marked E on the map) shows :— 
1. Marly subsoil ... . ..... 2ft. 
2. Yellow, sandy rubble, with angular and broken flints and 
small chalk pebbles. 
These three sections seem to indicate that after the removal of the 
boulder-clay from the valley in which they are found, and after the 
subsequent denudation of the valley until it attained its present 
depth, the first deposit brought down, perhaps partly by the stream 
running intermittently along it, and partly derived from the sub¬ 
aerial denudation of the slopes of the adjacent hills, was the bottom 
and principal bed in the sections, composed almost entirely of white 
chalk fragments, and of pebbles and flints derived directly from the 
chalk; indicating that the valley and adjacent slopes were free 
from clay and presented to denuding agents nothing but bare chalk. 
Above this we find in each place a subsoil, in the first case 
coloured by the brown clay which has given distinctive colouring 
to much of the country which lies near the now existing boulder- 
clay patches, and which I attribute to the gradual washing down 
from these patches of small quantities of the clay, and in the others 
white and marly where the immediately overhanging hill is now 
white and bare. 
As far as the purely local evidence goes I think that it supports 
my conclusions as to the course and character of events, and the 
changes in the configuration of the particular and limited district 
from which the evidence is derived. I do not pretend to carry the 
matter further, or attempt to bring into harmony with, or indi¬ 
cate the differences which may exist between, theories of the course 
of events as applied to more extended areas. 
I now proceed to note briefly a few other boulders in this part 
of the county. 
The large boulder at Eoyston has been fully described in our 
‘ Transactions.’* 4 Two smaller boulders at Eoyston are noted in 
the fifth Eeport of the Eritish Association Committee.f One 
of millstone-grit, 3ft. by 2ft. by 1ft., and a smaller sandstone 
boulder, were then lying in the garden of a house in Melbourn 
Street. 
Two boulders at Kelshall on the main ridge at a point at least 
500ft. above sea-level are referred to in the eleventh Eeport of the 
Committee.^ These are of special interest as showing that the larger 
boulders and those which have probably come from as distant a source 
as any in the district occur at the highest points reached by the hills 
of the district. There are other boulders in the village of Kelshall 
and in the neighbouring villages on the ridge. I quote from the 
Eeport:—The following boulders, when they were examined in 
* ‘ Trans. Watford Nat. Hist. Soc.,’ Yol. II, p. 249. 
t ‘ Report of the Brit. Assoc., 1877,’ p. 84. 
+ ‘ Report of the Brit. Assoc., 1883,’ p. 143, 
