271 
CHAPTER X. 
UPPER LIAS (continued}. 
Northamptonshire. 
THE Upper Lias of Northamptonshire and districts to the north- 
east, has been divided as follows, mainly in accordance with the 
divisions adopted by Prof. Judd* : 
rLeda-ovum Beds. 
Zone of Ammonites I Clays with few fossils (Unfossiliferous Beds of B. Thomp- 
communis. | son). 
LCornmunis Beds. 
Zones of A. serpentinus f Serpentinus Beds. 
and A. unnulatusA Paper Shales with Fish and Insect Limestones. 
(Basement Beds). [Transition Bed. 
The Paper Shales consist of finely-laminated bluish-grey shales, 
poorly developed in Northamptonshire (1 ft. to 18 ins.), but 
containing a band, or nodular masses, of pale grey or brown 
argillaceous limestone, a few inches thick, which yields Fish-remains 
find occasional remains of Insects. This division may be correlated 
with the lowest beds of the Upper Lias at Dumbleton in 
Gloucestershire. 
Saurian bones are rarely found. The Fishes include Lcjndotus 
cJrcnsis, Lcptolepis concentricus, and Pachycormus. Otolites of 
Fishes have also been found. The Ammonites include A. bijrons, 
A. communis, A. cornucopia, A. crassus, A. eleoans,^ A, Hol- 
andrei, A. Levisoni, A. serpentinus, and Aptychi. Among other 
fossils are Belemnites (rare), Inoceramus dulrius, Euomplialus (?) 
ininntus, &c. Lignite and Jet are occasionally met with, and the 
occurrence of Coprolites was noted by the Rev. P. B. Brodie. 
Mr. Beeby Thompson notes that the Fish-bed consists of fipsile 
nodules which are not concretionary, but appear in most instances 
to have been rounded by percolating water. (See p. 319.) 
The " Serpentinus " Beds consist of marly clays with an over- 
lying thin band, or nodules, of soft sandy and sometimes ferrugi- 
nous limestone (" Lower Cephalopoda Bed ") ; and they are 
about 5 feet thick. Mr. Thompson records Saurian bone? 
(rare), Ammonites bifrons (rare), A. communis ) A. cxaratus, A. 
Holandrei, A. serpentinus (falcifer), Belemnites, Nucula Hammcri, 
Gasteropods, &c. 
* Geol. Rutland, pp. 79, 89 ; see also B. Thompson, Journ. Northamptonshire 
Nat. Hist. Soc., vol. iii. p. 186. 
f Including the forms known as ^4. complanatus and A. im'bplniuitits ; for such 
forms the name A, radians was employed by Prof. .Tudd. 
