1870.] SHARP—NORTHAMPTONSHIRE OOLITES, Old 
headland, occupying the angle formed by the junction of the Nen 
valley with the broad valley through which passes the London and 
North-western railway. The road from Northampton to Blisworth 
ascends this hill, and passes over the junction of the Upper Lias with 
the lower beds of the Northampton Sand, marked by the presence 
of springs. On the ridge, near the Danes’ Camp, is a small petch of 
Great Oolite Limestone at aa; and upon the descent on the southern 
side, at 6b, the junction of ine white sand C with the beds D is 
observable. In the valley below, the Marlstone of the Middle Lias 
is the prominent surface-bed. 
At a distance of five miles from Northampton, in this direction, is 
Arras LY. Brisworts. 
The general section of this area varies in some particulars from 
that of each of the areas I have yet described. The high grounds 
are capped with a thick bed of Boulder-clay, containing rounded 
boulders of primary rocks, fragments of chalk and fi*nts, masses of 
Septaria, rounded blocks of indurated Oxford Clay enclosing nume- 
rous Ammonites and other fossils, &c. 
Between the Boulder-clay and the underlying Great Oolite Lime- 
stone, A, is a bed of very variegated and thinly stratified Great- 
Oolite clay, very full of small oysters (Ostrea subruqulosa). This 
clay occurs also in the same postion at Tiffield, about two miles 
8.W., and at Stowe Nine Churches, some six miles west. At the 
latter place it is seen at the top of the section of a mass of Great 
Oolite let down by a fault below the level of the neighwouring iron- 
stone ; the wall of which fault, sharply defined, is seen in the quarry. 
I have indicated the place of this clay in my General Section by the 
letter X. 
Another variation consists in the remarkable thinning of all the 
beds between the Great-Oolite limestone, A, and the lower beds, E, 
of the Northampton Sand. These beds, B, C, D, which represent 
in the General Section an aggregate thickness of from 55 to 60 feet, 
have here dwindled to a thickness only of from 8 to 10 feet. They 
have again thickened, however, in districts 8. & 8.W. of Bli-worth. 
A section of the Great-Oolite limestone is graphically seen in the 
cutting of the railway between the Blisworth and Roade stations ; 
but it may be more particularly examined in the ancient and large 
quarry to the 8.E. of the village. This quarry is approached from 
a point near to the N.E. entrance of the great tunnel of the Grand 
Junction Canal; which tunnel, cut to a length of nearly two miles 
in the Upper Lias clay, constituted one of the great engineering 
works of the last age. 
The following is the section in this quarry :— 
Section of the Blisworth Great-Oolite Limestone Quarry, with Quarry- 
men’s Terms. ft. in.) pita in. 
MS BOulMCy-Clay....cccsscsccsecnesscnesevessesoeescenssanenneespanien 1l Oto 12 0 
2. “ Rammel”—clay, very variegated (green, yellow, brown, 
blue, and black), thinly stratified, full of Ostrea swb- 
rugulosa, and containing WOOK ...s..seesse veneers Ldeaaie 1 6to 2 9 
VOL, XXVI.—PART I, 2D 
