230 
THE MIDDLE LIAS OF NORTHAMPTONSHIRE. 
envois pourraient vous occasionner. Je regarde comme un 
devoir pour tons ceux qui partagent les idees de notre illustre 
maitre, Herbert Spencer, de joindre leurs efforts pour propager 
ses belles doctrines qui constituent aujourd’liui Tun des plus 
sublimes monuments eleves a la science et a la pliilosophie. 
Recevez, clier Monsieur, avec mes remerciments anticipes, 
l’assurance de ma haute consideration. 
James Grosclande, 
Ingenieur Civil, 
96, Boulevard Diderot, Paris. 
THE MIDDLE LIAS OF NORTHAMPTONSHIRE. 
BY BEEBY THOMPSON, F.G.S., F.C.S. 
( Continued from page 207.) 
II. —Would the Water go into the Middle Lias Beds? 
6.—There are two or three special matters bearing upon 
the question of the porosity of the Middle Lias which require 
some consideration. It has been rather insisted upon by 
some of the opponents of this water scheme that the water 
in the Marlstone travels only by means of cracks and fissures 
in the Rock-bed. I am quite prepared to admit that these 
fissures very materially aid the circulation of water in the 
Marlstone, but I am also quite certain that this is not the 
only way by which water travels. 
If water travelled only by means of these fissures, an 
uninterrupted series of them must extend from the well 
where water is obtained to the outcrop of the bed, or catch¬ 
ment area, and then the water supply would vary with the 
season, but so far as I can ascertain, this is not the case with 
any deep well in the Marlstone; also, the finding of water 
would be much less certain than it is, and its efficient filtra¬ 
tion doubtful. 
No doubt the idea that water circulates only by means of 
fissures arises from the fact that when a well is made such 
cracks are commonly met with, and water appears to issue 
from them only; they not only form miniature wells for the 
water to flow into, but may extend some distance into the 
rock laterally, and so act as headings m draining it. 
The extreme rarity of wells in the Marlstone not yielding 
water has previously been pointed out; nevertheless, much 
