280 LIAS OF ENGLAND AND WALES : 
levidensis ?, B. subaduncatus, Gresslya donaciformis Trigonia 
northamptonensis, and other species previously mentioned from the 
Upper Leda-ovum Beds (p. 273). The species of Ostrea are 
identified by Mr. Thompson as 0. sandalina and O.falciformis. 
The junction between the clay and overlying Northampton 
Beds, as noted by Mr. Thompson, is sharply defined, and the two 
formations appear comformable. Nevertheless the presence of the 
rolled masses of limestone on top of the clay, is suggestive of some 
local break ; and if we regard the clay as belonging to the zone of 
A.jurensis as Mr. Thompson maintains, we must I think consider 
that the zone is only partially represented.* 
At Kettering brickyard we find the Upper Lias clay, yielding 
many fine crystals of selenite. The beds have yielded Ammonites 
bifrons, but represent the unfossiliferous type of the series. 
Several sections in the neighbourhood of Kettering are described 
by Mr. Thompson ; in brickyards on the road leading towards 
Geddington, and on the Barton road, where he has obtained many 
fossils indicating the Upper Lcda-ovum beds. Similar beds 
have been opened up between Great Harrowden and Isham, and 
the Unfossiliferous Beds have been worked at Orton, near 
RotkweH. 
A boring in the Upper Lias between Kettering and Weekley 
appears to have reached the Marlstone at a depth of 44 feet. 
The Oxenden Magna tunnel, on the London and North- Western 
Railway, leading from Market Harborough to Blisworth, passed 
through the Upper Lias clay, which is here thickly covered with 
Boulder Clay and other Drift. In the heaps o clay brought out 
from this cutting numerous Upper Lias fossils were collected by 
Prof. Judd, including the following: t 
Ammonites serpentinus. Ammonites communis. 
falcifer. j Holandrei. 
Northamptonshire (continued), Rutlandshire, and 
Leicestershire. 
Prof. Judd remarks that : " The great mass of Upper Lias in 
this area, which stretches from the north of Wymondham to 
south of Braybrook, and attains its greatest breadth between 
Tilton-on-the-Hill and Barrowden, is intersected by many 
winding valleys, which cut down deeply enough to expose the 
Middle Lias strata, sometimes forming inliers in the midst of 
the Upper Lias. On the other hand, the higher portions of the 
Upper Lias are capped by the beds of the Inferior Oolite, 
which form outliers, often of great size, scattered over the 
district of the Upper Lias. The valleys which breach the 
great escarpment of the Inferior Oolite, namely those of the 
rivers Gwash, Chater, and Welland, and their numerous tribu- 
taries, are cut down to the level of the Upper Lias, but the 
* See also remarks by W. D. Crick, and J. F. Blake, Proc. Geol. Assoc., vol. xii. 
pp. 188, 189. 
f Judd, Geol. Rutland, p. 81. 
