Vol. 58. ] SOME GAPS IN THE LIAS. 269 
brachiopoda, after the manner of their occurrence at the present day 
in the great Australian Barrier-Reef. 
Kast of the Cherwell Vale the Ferrocrinoid-Beds lose type and 
importance. Along the Middle Liassic outcrop, on the north-western 
border of Northamptonshire, and trending eastward into Rutland, 
the same Ferrocrinoidal life appears to have prevailed, though 
perhaps less prominently. In the famous iron-ore-field of Cleve- 
land it was a great factor in the making of the Liassic limestone, 
though of difference in type from the Oxfordshire beds. 
Passing to consideration of the close of the Ferrocrinoid time, I 
think it is certain that the area of deposition was narrowed, or that 
waste over wide areas has supervened. We have been too prone to 
assume that the fact that several zones are welded into one course of 
limestone constitutes sufficient evidence of continuity of conditions. 
I shall show, by three sections from the neighbourhood of Banbury, 
that such conditions do not prove continuity. 
At Bloxham, 3 miles north-west of that town, the 3 feet of the 
Liassic rock-bed at the top form one course, in the main made up 
of the stems of the Ferrocrinoid, but passing at the junction with 
the Upper Liassic clays into pinkish compact limestones crowded 
with Upper Liassic organisms. The pink limestones are of the 
Ammonites-communis zone, the intermediate Transition-Bed and 
zone of Ainm. serpentius having been removed by inter-waste. 
At Fernhill, 6 miles north-west of Banbury, the rock-bed 
(Amm.-spinatus zone 2) is overlain by the Transition-Bed (6), the 
Posidonomya-shales and limestones of the zone of Amm. serpentinus 
(¢c), and by thin fossiliferous limestones and thicker clays of the 
zone of Amm. communis (d). Rather high up, a thin limestone, 
made up of Pentacrinite-segments, constitutes a convenient line for 
demarcation. At the eastern end of the same cutting at Fernhiil, 
the conditions of the Bloxham section are shown in the removal of 
the Transition-Bed and the whole of the zone of Amm. serpentinus. 
This is even more clearly shown at the Astrop Ironstone Company’s 
works at Cobbler’s Pits, near King’s Sutton, where remains of certain 
of the fossils of each horizon prove a former continuity of zones. At 
Fawler, the farthest point south-westward, yet more waste is shown, 
the zone of Amm. bifrons being indicated by a few fessils charac- 
teristic of its limestone, of the same species as at Bloxham. 
On the north-western border of Oxtordshire, where the Ferro- 
crinoidal ironstone is of greatest thickness, the Upper Lias has been 
removed for the most part, and here and there a patch with the 
limestone of the zone of Amm. bifrons welded with the limestone 
of Amm. spinatus shows an equal amount of inter-waste. The 
preservation of the several zones has been effected by the earlier 
subsidences of the Eastern Cherwell border, and by another small 
area of subsidence of the western border of Oxfordshire, where the 
fall is to the west and the River Avon. They are both in the areas 
of a divide—the one in the divide of the drainage of the Ouse and 
Cherwell, the other in the divide of the Avon and Cherwell. 
However complete the sequence of the sections may appear to be, 
