252 
THE MIDDLE LIAS OF NORTHAMPTONSHIRE. 
Bed “C.” 
It is even more uncommon to find this bed exposed than 
“ E,” and I cannot point to a single place in the county where 
it can be now seen. There was a pretty good section of it near 
to Byfield, when the East and West Junction Kailway was 
being made, and Mr. E. A. Walford, F.Gf.S., has described 
it* as a marly clay, containing concretionary ferruginous 
nodules, having a thickness of 1ft. Gin. No doubt this and 
two or three of the lower beds are what can be seen at 
Market Harboro’, near to the railway station. 
Bed “ B.” 
The Rock-Bed. 
This is undoubtedly the most important bed of the 
Middle Lias. Its usual character is that of a hard, calcareous, 
and ferruginous rock, varying in colour from a bluish green 
to a reddish brown, according to the amount of weathering it 
has experienced. The change in colour is due to a change in 
the condition of the iron present in it. The rock is often 
sufficiently hard and compact to form a good building stone, 
and many villages have been built of it, but of late it has 
been almost entirely superseded by bricks for such purposes ; 
in like manner it has been replaced by slag and Hartshill 
stone for public road-making, though it is still used at times 
for private roads and sometimes of course for building. 
The rock is also at times sufficiently ferruginous to be 
worked as an ironstone, the calcareous matter present being 
considered an advantage by acting as a flux. 
It is sometimes so sandy that it can scarcely be dis¬ 
tinguished from the Northampton sand by its mineralogical 
characters only ; this is the case around Byfield. Fossils 
are exceedingly abundant, and it is common to find bands 
made up almost entirely of ossicles and fragments of shells , or 
of shells of Rhynchonella, or less commonly of Terebratula. 
Usually the fossils contain beautifully crystallized calcspar, 
though where the bed is very sandy the fossils are only casts. 
Large Belemnites are common, and serve to distinguish it 
from the Northampton sand, in which few are found. 
In the lower part of the bed flattened nodules or concre¬ 
tions of argillaceous limestone are at times met with ; they 
are rather abundant at Bugbrook. 
* “ On some Middle and Upper Lias Beds in the Neighbourhood of 
Banbury,” by Edwin A. Walford. 
