202 LOWER OOLITIC EOCKS OF ENGLAND : 
Prof. Judd states that the plant-markings which occur in the beds 
(d) and (e), appear to indicate that plants actually grew upon the spot, and 
were embedded as they stood, by the quiet deposition of fine sediment 
around them. The beds called " root-beds " by Prof. Morris, which occur 
in the Upper, Estuarine Series, greatly resemble (d). The clay of (d) is 
very fine-grained, and the surfaces of its laminas are covered with scales of 
mica : in it the carbonaceous matter is always preserved, while in the sands 
below (e) it is more frequently removed, and the sides of the empty tubes 
are stained with oxide of iron. In descending through the lower beds of 
sand (h) we find them more and more impregnated with oxide of iron, 
which exists as a coating around the individual grains ; when this coating 
is removed by the action of acid, a white sand remains similar in every 
respect to that forming the bed (</). From the statements of workmen it 
appears that this ferruginoiis character still increases in going deeper, and 
that the bed which rests directly on the Lias Clay is a thin band of the 
ordinary ferruginous rock of the Northampton Sand. 
Another section, between Ufford and Marholm, is shown in 
Fig. 56. 
Near Helpstone Heath Farm the sands have been well exposed. 
They are much false-bedded, and contain (according to Prof. 
Judd) in some layers, Pinna cuneata, *Ostrea acuminata, Tri- 
gonia pullus ; and in others, numerous Cyrence. The base of the 
sands is not seen in this pit, but in another in the vicinity, the 
white sands are found resting directly on the Upper Lias clay, 
without the intervention of any ferruginous rock. The total 
thickness of the Northampton Beds at this place is rather more 
than twenty feet. Towards the west and south of Helpstone, the 
thickness of the ferruginous rock increases.* 
At Water Newton brickyard the following beds have been 
provedt : 
FT. IN. FT. IN. 
Upper Estuarine / Sands and clays, with nodular 
Series. \ ironstone at base - 3 to 9 
} Fine grained oolitic limestone 1 3 to 4 
Northampton / Clays and sands with ironstone 
Beds. t beds at base - - 16 to 18 
Upper Lias Ciay. 
Both Lower and Upper Estuarine clays have been worked here 
for brick-making, and the Koman potteries of Durobrivae or 
Castor were situated hereabouts. Eastwards as before mentioned 
the Lincolnshire Limestone disappears ; and at New England, 
Peterborough, a boring was made to a depth of 428 feet, the 
strata after a depth of 78 feet being blue clay and stone. No 
supply of water was obtained. It is probable that the boring 
was commenced after the Cornbrash had been excavated. The 
details may be grouped as follows : J 
* Judd, Geol. Rutland, pp. 104-106 ; Sharp, Quart. Journ. Geol. Soc., vol. xxix. 
p. 272. 
Jfjudd, Geol. Rutland, pp. 99, 100, 171, 189. 
J~See also Porter, Geol. Peterborough, p. 98. 
