Vol. 58. ] SOME GAPS IN THE LIAS. 273 
shire; to the east it comes in at Fernhill, and extends thence to 
Bloxham on the south-west side of Banbury. Its areal have traced 
for 20 miles north and south by 10 miles east and west. Between 
the fish-bearing limestones of the Ammonites-serpentinus zone and 
the overlying Pentacrinite-band at Byfield but a few inches of 
strata occur; at Fernhill there is a thickness of 123 feet. At 
Bloxham the Pentacrinite-Limestone rests upon an argillaceous 
limestone of the lower part of the zone of Ammonites communes, 
with only 3 feet of deposit between the crinoidal limestone and the 
Middle Liassic rock below. A thin yellow limestone of the same 
zone lying upon the Middle Liassic rock I term ‘the hemera of 
Waldheimia Lycetti, and it yields a large and special fauna. At 
Fawler only a trace of it rests directly upon the Middle Lias. 
At Fernhill, within the mile’s length of the long cutting on the 
Great Central Railway, differences in sequence of strata are found, 
which elsewhere have to be sought for over wide areas of adjoining 
country. Fernhill is in itself the key to the right sequence of the 
stratigraphy of the Middle and Upper Lias, though in other 
localities paleontological stations are better marked. The Penta- 
crinite-Limestone rests upon the Ammonites-communis rock in places 
where the intervening beds have wasted, and the occurrence of 
Waldheimia Lycetti marks the hemera there. The subsidence or 
fault which runs along the line of railway at Fernhill breaks the 
bed on the west bank of the cutting abruptly down, and the Wald- 
heimia-Lycetti beds are seen to rest upon the Middle Liassic ironstone 
in much the same way as at Bloxham. Worn out on it are great 
cable-like markings, bearing the appearance of remains of massive 
arborescent or trailing growth. The waste of the ‘ funnel-fault’ at 
Fernhill has removed the strata of the intervening zones, in the 
same way as the slower and long-continued inter-waste has done 
on the 10-mile long slopes of the country from the western Middle 
Liassic outcrop to the banks of the Cherwell. 
The measure of displacement of the Lias over the Cherwell Vale 
may be gathered by noting that the Ammonites-margaritatus zone 
at Fernhill occurs at the altitude of 570 feet near the divide of the 
Ouse and Cherwell, while on the western escarpment the altitude of 
the same beds I take to be 680 feet; fragments of the same zone 
along the river-banks are found at about 300 feet above Ordnance- 
datum. What was the old line of altitude is beyond our ken of 
today. 
The key to the problem of inter-waste is sought in the necessarily 
associated lines of fall and drainage. Our local conditions show that 
the long fall from the escarpment south-eastward lessens the thick- 
ness of the Middle Liassic calcareous ironstone only as it nears the 
main line of drainage (the Cherwell). The thickness ranges from 
30 to 10 feet. The drainage on the east side of the Cherwell with 
a south-westerly fall, and of but one third of the area of that to the 
west, alters the rule. Twelve feet may be taken as the maximum 
of the Middle Liassic calcareous ironstone—the thickness ranging 
from 6 to 12 feet irregularly over that region. 
