554 Notices of Memoirs—Prof. Hull— Water in Trias. 
for the most part was run off into cesspools sunk in the sandstone 
rock on which the town is built; and as regards the latter the 
water-supply was drawn from wells sunk through the same for- 
mation down to the water-level, so that often the cesspools and 
wells were in proximity to each other. The result of such a state 
of affairs may easily be surmised. However excellent as a filter 
may be the sandstone rock, it must assuredly become clogged with 
feecal matter when filtration of water is carried on for an indefinite 
period, subject to such contamination as is here referred to, and 
in course of time the water from the wells becomes unfit for drinking 
and household purposes. 
Now all this is changed: the cesspools have been closed or 
filled up, and the water-supply is drawn from large and deep 
wells far removed from possibility of contamination. 
Few towns in central England are more favourably situated for 
purposes of water-supply than Nottingham. Built on a foundation 
of New Red Sandstone and conglomerate, which rises at the Castle 
in a precipitous cliff above the valley of the Trent, the formation 
on which the city stands in its prolongation northwards is a source 
of water-supply of the highest excellence, and yields several millions 
of gallons per day of pure water from three or four wells situated 
within a few miles of the city. 
The conditions which render this formation so well adapted 
for water-supply may be briefly explained. The succession and 
character of the strata all combine towards this end. 
In descending order the succession is as follows :— 
Keuper Maris . . . Red and variegated marl, shaly and 
gypseous (slightly permeable). 
Waterstones and Lower Laminated micaceous sandstones alter- 
TEnsy Keuper Sandstone nating with marls and shales. 
Bunter Sandstone . . Soft yellow and reddish sandstone and 
conglomerate (permeable). 
Red Calcareous Maris. These are the strata separating the 
Pp Upper and Lower limestones of 
ERMIAN 
the Worksop district to the north 
(impervious). 
Lower Magnesian Lime- Sandy magnesian limestones. 
stone 
From the above succession it will be seen that the permeable 
beds of the Bunter Sandstone, about 800 feet in thickness, are 
underlain by impervious marls of the Permian series, which thus 
form a water-tight floor, effectually preventing the water which 
percolates downwards from the surface to escape into the magnesian 
limestone; and, as the beds dip eastwards at a small angle from 
the western margin of the formation, an underground reservoir is 
thus formed with a naturally permanent level corresponding to 
that of the springs which break out at the junction of the sandstone 
with the marl along the western outcrop. 
The proportion of the rainfall, taken at an average of 30 inches, 
which sinks down into the Bunter Sandstone north of Nottingham 
must be very large, owing to the absence of drift deposits and the 
sandy character of the ground. As there is no surface drainage 
