86 
THE MIDDLE LIAS OF NORTHAMPTONSHIRE. 
The various springs of the county may, for present 
purposes, be classified as below :— 
1. —River Gravel Springs. 
2. —Drift Gravel Springs. 
3. —Great Oolite Springs. 
4. —Inferior Oolite Springs. 
5. —Marlstone Springs. 
6. —Trias Springs. 
The River Gravel Springs.— Along most river valleys 
there is on each side of, and below the present restricted 
water channel, an accumulation of matter newer than the 
river itself, and evidently owing its accumulation to that 
river. This alluvial matter, in the case of the Nen Valley, 
consists of a deposit of sand and gravel, covered in the lowest 
parts of the valley by a dirty looking mud or clay containing 
much vegetable matter. 
The River gravel apparently dips below the present river 
and its alluvial clay bed, but rises some little distance above 
the ordinary level of the river on each side, forming low 
meadow lands, or in some cases, as for instance in the Cow 
Meadow at Northampton, a distinct river terrace. This bed 
is of Paleolithic age, and has yielded numerous remains of 
the Elephant (two species), Rhinoceros (two species), Hip¬ 
popotamus, Ox, Horse, Wild Hog, and Red-deer, and also a 
few flint implements. 
The bed is sometimes worked for gravel in Northampton, 
and an extensive bed of it between Barnwell and Oundle is 
worked by the railway company for ballast. 
The Alluvium proper is practically impervious to water, 
and certainly more recent than the gravel. It contains the 
remains of the Ox, Red-deer, Horse, Wild-hog, and numerous 
freshwater gastropods, such as Anodonta, Physa, Planorbis, 
Limnea, &c.; also human remains. The thickness of the 
alluvium is very variable. The clay and gravel together may 
reach thirty feet or more in places, and where both are 
present they seem to have a thickness inversely to each other, 
though on this point I cannot speak very definitely. 
The river gravel rests upon Upper Lias clay, and hence 
we have all the conditions for the formation of a Land Spring , 
and such a spring we find. 
Some few wells in Northampton are fed by water from this 
river gravel, and it was even proposed to utilise it for the 
water supply of the town, but this scheme fortunately found 
little favour, as also a proposal to pump it into the same 
reservoir with water from other sources. 
