OVERLAP OF STRATA. 3 
Eastwards of the Cotteswolds we have higher members of the 
Inferior Oolite overlapping lower members (from W. to E.); and 
in this Midland region we have evidence of unconformable over- 
lap of the Great Oolite Series, which traced from Lincolnshire into 
Northamptonshire (from N.E. to S.W.), rests in places on lower 
and lower portions of the Inferior Oolite Series. Again in the 
eastern part of Northamptonshire and in Bedfordshire, the Great 
Oolite Series rests on attenuated beds of the Inferior Oolite Series, 
and finally overlaps them, so as to rest directly on the Lias. In 
some localities there is more marked evidence of local disturbance 
and erosion between members of the Great and Inferior Oolite. 
(See Fig. 51, p. 188.) Again in the area extending from -Bath to 
Dorsetshire, we find a considerable overlap of the Forest Marble 
where it stretches across the Great Oolite on to the Fuller's Earth, 
and this overlap was probably attended by local erosion. (See 
Fig. 80, p. 255.) 
With regard to the former extent of the Oolites, we have no 
evidence whatever for marking the limits of their formation west of 
the main outcrop. Eastwards and south-eastwards, we know that 
Oolitic rocks are absent beneath the Cretaceous and Tertiary 
coverings at Harwich and Ware; but some members of the series 
have been proved in deep borings at Richmond, under London, 
at Streatham, Chatham, and Dover. In this subterranean area, 
as in the Boulonnais, the Great Oolite is found to have overlapped 
the lower members of the Oolitic Series- and the Lias, so as to 
rest directly on the Pala3ozoic floor : and it is not unreasonable 
to conclude that land existed in the area during some portions 
of the Jurassic period. (See p. 360.) We cannot tell for certain 
how far the absence of Jurassic beds in the eastern portions of 
England (Harwich, Ware, &c.) may be due to denudation prior 
to the Upper Cretaceous period ; but we know that much destruc- 
tion took place locally in Lower Cretaceous times, from the 
unconformable overlap of the Lower Greensand, and from the 
occurrence of derived Jurassic fossils in that formation in Bedford- 
shire and other parts. 
The general relationship of the leading sub-divisions of the 
Oolitic Series is shown in the Table on page 4 ; and the principal 
local breaks are indicated by wavy lines. 
The several subdivisions of this Series are all more or less 
intimately linked together: thus the Midford Sand links the Lias 
with the Inferior Oolite ; and the Fuller's Earth (which is inti- 
mately connected with the Stonesfield Slate) links the Inferior 
Oolite with the Great Oolite. It appears likely that the uppermost 
portion of the Inferior Oolite in Oxfordshire, locally known as the 
Chipping Norton Limestone, is coeval with portions of the 
Fullers Earth Clay elsewhere. Again, the Cornbrash and Kella- 
ways Rock, and the succeeding beds of the Middle and Upper 
Oolites are all closely bound together, and locally pass up into the 
Wealden Beds without any evidence of a break in the succession. 
An Lincolnshire, as pointed out by Mr. A. Strahan, there is 
nience of unconformable overlap between the Kimeridge Clay 
A 2 
