209 
THE MIDDLE LIAS OF NORTHAMPTONSHIRE. 
THE MIDDLE LIAS OF NORTHAMPTONSHIRE. 
BY BEEBY THOMPSON, F.G.S., F.C.S. 
Part I. 
(Continued from page 188 .) 
Some Sections Illustrating the Development of the 
“ Margaritatus ” Zone in Northamptonshire. 
The number of sections in which the “Margaritatus” 
Zone can be studied is not large, but the beds of which the 
zone is made up are as interesting, paleontologically, as any 
in the Middle Lias. The section given below cannot now be 
seen ; it was worked a short time for stone, and then covered 
up again. The situation is on the side of a steep hill over¬ 
looking Banbury, about a mile or more from Chalcomb, and 
quite away from any road. 
Section near to Gibbard’s Farm, Chalcomb. 
’ Feet. In 
1. —Soil and light-coloured clay ... ... 8 0 
2. —Sandy clay or shale, light brown colour, 
micaceous and ferruginous, joints red ... 2 3 
3. —Band of ironstone concretions, with some 
small pebbles, containing :— Modiola, 
Astarte striato-sulcata, Ar corny a hispida, 
Pecten cequivalvis , Avicula incequivalvis, 
Small ammonites (probably A. maryari- 
tatus) ... ... ... ... ... 0 9 
4. —Sandy clay or shale, light brown colour, 
highly micaceous, joints and surfaces 
reddish. No effervescence with acids:— 
Ammonites margaritatus (small specimens), 
Avicula incequivalvis, Pecten cequivalvis, 
Pecten liasinus, Modiola, Protocardium 
truncatum, &c. ... ... ... ... 2 7 
5. —Hard calcareous rock, mottled in places, 
and containing much crystallised car¬ 
bonate of lime. Highly fossiliferous, 
but the fossils difficult to extract or 
identify in the stone :— Ammonites sp ? 
Ostrea, Limeci acuticosta ... 
Good spring of water. 
The hard bed, No. 5 (“L” of typical section), contained 
some very pretty pieces of stone, pieces full of little cavities 
partially filled with crystallised carbonate of lime (congealed 
