INFERIOR OOLITE C OXFORDSHIRE. 147 
Great or Bath Oolite. Upper Zone. 
Northampton Sand (Sands, calc. sandstones, ironstones, and lime- 
stones) 
Upper part = Lower Zone of Great Oolite. 
Lower part = Inferior Oolite. 
Inferior Oolite. (Clypeus Grit.) 
The construction of a line of railway from Chipping Norton 
to Banburj has exposed a number of sections, clearly showing 
the presence of the upper and lower portions of the Great 
Oolite the latter comprising the Stonesfield Slate division, 
which here, as in other places, appears to be intimately connected 
with the Fuller's Earth. These beds will be described further on, 
but it may be stated that where fully developed, as west of 
Bourton-on-the- Water, there is no discordance between them and 
the Inferior Oolite Series below. In other cases there is consider- 
able unconformity. 
Near Chipping Norton, the Inferior Oolite Series comprises a 
very variable set of beds, the uppermost portion of which is a 
thick mass of hard oolitic and sandy limestones (Chipping Norton 
Limestone), while, at lower horizons, we have evidence of the 
Clypeus Grit, and of beds of white and brown sand, calciferous 
sandstone, and occasional oolitic beds, the precise relations of 
which are exceedingly difficult to determine. 
It would appear that the divisions of the Inferior Oolite are 
inconstant in extent, as Avell as variable in character, overlapping 
some of the minor divisions, while they are overlaid irregularly by 
different portions of the Great Oolite Series, which thus rests un- 
conformably on various members of the Interior Oolite. By the 
light of recent researches there will be much less difficulty in dis- 
tinguishing Great Oolite from Inferior Oolite ; but this has yet to 
be done on the Geological Survey Maps in the country around 
Chipping Norton portions of the Great Oolite being included in 
the " Northampton Sand " in some places, and of Inferior Oolite 
in the " Great Oolite " and " Stonesfield Slate " of other areas, 
more especially between Chipping Norton and Stonesfield. 
The observations of Mr. T. Beesley, and of Mr. E. A. Walford, 
of Banbury, of Mr. J. Windoes, of Chipping Norton, and of Mr. 
W. H. Hudleston, have tended largely to elucidate the structure 
of the district, and to augment our knowledge of the fossil contents 
of the strata. Many difficulties, however, still remain for future 
workers. Sections are not sufficiently abundant to clearly show the 
relations of all the subdivisions of the Inferior Oolite, to demonstrate 
their lateral variations or attenuation ; and, where fossils are rare 
or absent, it is not always possible to say to which particular division 
or " zone " of the Inferior Oolite every outlying mass or isolated 
section of the beds may belong ; for faults, as well as irregular over* 
laps, serve to complicate the geology of this area. Indeed it is 
not unlikely that some undulations affected the Inferior Oolite 
prior to the deposition of the Great Oolite ; and owing to denuda- 
tion, the Great Oolite thus rests irregularly on different members 
of the Inferior Oolite. (See p. 325.) 
K 2 
