THE MIDDLE LIAS OF NORTHAMPTONSHIRE 
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in abundance, together with a fair number of specimens of 
Protocardium truncatum and Pleuromya costata. At Staverton 
it is almost an ironstone, and somewhat cellular in structure ; 
Pholadomyas are not so common, but Protocardium truncatum 
more so. I believe the latter fossil is more common in this 
bed than in any other bed of the Middle Lias of Northampton¬ 
shire. It is found in masses—somewhat like Rhynchonella 
tetrahedra in the Rock bed—at certain places. Thickness at 
Staverton, 2ft. 9in. 
Fossils. 
Ammonites margciritatus... Byfield. 
Ostrea cymbium . Staverton. 
Pectcn liasinus . Byfield. 
Limea acuticosta . Byfield. 
Avicula inaquivalvis .Byfield, Staverton. 
Area elongata . Staverton. 
Modiola numismalis . Byfield. 
Protocardium truncatum ... Byfield, Staverton, &c. 
Cardita multicostata . Staverton, Byfield. 
Pholadomya ambigua . By field, Staverton. 
Pholadomya Simpsoni . Byfield. 
Pholadomya ohtusalis . Byfield. 
Pleuromya costata . Byfield, Staverton. 
Arcomya concinna (?). Staverton. 
Ceromya petricosa . Byfield. 
Goniomya heteropleura _Byfield. 
Isocarclia liassicci (?). Byfield. 
Pentacrinite stems . Staverton. 
Wood, and cavities left by 
stems of plants . Byfield, Staverton. 
Calc spar—a little . Byfield. 
Bed “ G.” 
This bed is a micaceous sandy clay or marl, of a dark blue 
colour when first exposed, but getting much lighter coloured 
on exposure ; it appears to contain fewer fossils than any of 
the beds below it. There was a very good exposure of it near 
to Byfield during the making of the East and West Junction 
Railway, where it was found to measure 6ft. 2in. It may be 
seen at Staverton , but it is so situated that I have not been 
able to measure it. It is probably between 6ft. and 7ft. in 
thickness near Northampton. I have found no fossils in this 
bed that are not also in the beds both above and below it. 
Bed “ F.” 
A soft, sandy, ferruginous limestone, generally slialy, and 
very fossiliferous, some parts being made up of comminuted 
