UPPER LIAS : BLISWORTH. 277 
record of a well near Stony Stratford, however, gives no definite 
indication of these intervening strata : beneath the Great Oolite 
limestone, there is said to be 88 ft. of clay, and this probably 
includes the Upper Estuarine Series. (See p. 230.) 
Inlying exposures of Upper Lias have been mapped at Stoke 
Goldington and Weston Underwood, between Olney and Newport 
Pagnel. I have examined the exposures, in company with Mr. 
A. C. G. Cameron, and we found no evidence of Upper Lias. 
The clays exhibit green and purple tints, like the Upper Estuarine 
Beds with which I think they should be grouped. The occur- 
rence of" Nail-head spar " in the clay at Stoke Goldington brick- 
yard might be taken as suggestive of Upper Lias ; but bands of 
fibrous carbonate of lime or " beef," are not uncommon in the 
Upper Estuarine Beds, and the " cone-in-cone " structure of the 
nailhead spar, seems to be intimately connected with the " beef." 
It is, however, not unlikely that in this neighbourhood, as further 
westward, the Estuarine clays may, in places, rest directly on 
Upper Lias clay, for the Northampton Sands become much 
-attenuated, and may not always be present. 
Northwards the outcrop of the main mass of Upper Lias clay 
continues near Stowe-nine-churches and Blisworth by Northamp- 
ton, and along the course of the Nen Valley and its tributaries. 
Stowe Brickyard east of Stowe-nine-churches, and south-west 
of Nether Heyford, showed the following section, to which I was 
conducted by Mr. Beeby Thompson : 
Northampton Sands - Brown ironstone. 
{Grey and brown clay. 
Blue slightly calcareous clay with calcareous 
nodules and " nail-head spar " (cone-in-oone). 
Small Gasteropods ( Cerithium armatum), Ammonites bifrons, A. 
Jibulatus, and A. heterophyllus are found in the clays, so that there 
is no evidence here of the highest stages of the Upper Lias, 
grouped by Mr. Thompson with the zone of A. jurensis, 
FiG. 89. 
Section at a Brickyard near Gayton Wharf, Blisworth, 
Northamptonshire. 
b. Boulder Clay, 3 feet. 
a. Upper Lias clay (much contorted), with ferruginous nodules and selenite 
shown to depth of 1 5 feet. 
