IN NORTH HERTFORDSHIRE. 
37 
boulders were met with, they seem generally to have been carted 
into the villages for use in paving and building and as blocks at 
the corners of buildings. There is only one small pit now open 
on Clay Bush Hill. The section is very irregular and presents no 
features of interest, but it may be worth recording, if only to give 
a general idea of the miscellaneous character of the deposit. The 
following are my notes of the section marked C on the map. 
Three sections in various parts of the pit are given. 
I. 1. Clayey subsoil, with a few angular flints ... 1ft. 6ins. 
2. Gravel of chalk-pebbles, angular flints, and sand . Oft. to 2ft. 
3. Fine, stratified, brown sand, with beds of small 
pebbles . Oft. to 4ft. 
4. Gravel of chalk-pebbles, angular and iron-stained 
flints, ferruginous nodules, and fragments of de¬ 
rived rocks (boulders). 
II. 1. Subsoil. 
2. Blue, chalky, boulder-clay . . 3ft. to 4ft. 
3. Fine sand. 
III. 1. Subsoil. 
2. Clay . 1ft. 6ins. 
3. Sand . 1ft. 
4. Gravel. 8ft. 
Where this patch of clay and gravel is cut by the railway at its 
southern end, the section is now too much obscured by the slipping 
down of the clay to give much information. It shows, however, 
that the clay lies in a depression or trough in the chalk, being 
perhaps 20ft. thick in the centre of the depression, and that it has 
at its base an irregular bed of conglomerate or breccia consisting 
of flints, mostly iron-stained and sub-angular, in a dark matrix. 
In a small outlier from, and to the JST.E. of, the main mass, also 
in a depression in the chalk of some depth, but which is an excep¬ 
tion to the general rule, and lies on a hill somewhat lower than 
adjacent hills which themselves are bare of clay, large excavations 
for clay and gravel have been made at different times. Here a 
bed of dark bluish clay, with chalk-pebbles, large septariae, and 
Ostrece and Belemnites from the Oolites and the Lias clays, rests 
on miscellaneous beds of sub-angular flints, and gravels, and 
sands of various textures. In these gravels large Belemnites , and 
specimens of Gryphcea areuata , are not uncommon, and in the fine 
sands small fossils from the Chalk occur (principally spines of 
Echini and specimens of Terebratulina gracilis). 
In the ninth Beport of the British Association Committee* I have 
given a list of nearly two hundred boulders and pebbles from Clay 
Bush Hill now lying in Ashwell. The notes in this paper will 
necessarily be founded upon this list. The particulars given in the 
list are very brief, and I propose now to supplement them by an 
analysis and summary of what may be arrived at by an exami¬ 
nation of the materials of the boulders, and their size and super¬ 
ficial characteristics. 
In the first place I give a list of the larger specimens, selecting 
* ‘Beport of the British Association, 1881,’ pp. 207-217- 
