522 RevieiDS — Horace B. Woodward — Lower Oolitic Hocks. 



district it is possible to subdivide them, as Mr. Buckman has lately 

 done, into sub-zones or hemeree. In the far more bulky deposits 

 of the Cotteswolds such precision is scarcely possible ; whilst in the 

 Inferior Oolite of Lincolnshire, where as a rule a thoroughly non- 

 Cephalopod facies prevails, any subdivisions which may be attempted 

 in the limestones must be based on the general character of the 

 fauna rather than on Ammonites which are seldom in evidence. 



The varying development of the Inferior Oolite, in its local 

 details, is well worked out in Chapters iii. to vii., as this protean 

 formation is followed from the thin but highly fossiliferous ironshot 

 oolites of Dorset and part of Somerset, through the thick false- 

 bedded oolites and ragstones of the Cotteswolds, into the sandy 

 limestones of North Oxfordshire. In this region the Inferior Oolite 

 begins to suffer an eclipse even on the outcrop, whilst on the dip 

 generally we know that it thins out to nothing beneath the over- 

 lying Bathonian, the highest beds in most cases being widely 

 transgressive over all the others. The typical developments in 

 the counties of Northampton and Lincoln, which belong to the 

 northern or Yorkshire province of the Inferior Oolite, are partly 

 foreshadowed in North Oxfordshire, as, for instance, at Otley Hill, 

 where, beneath 3 feet of Eagstones representing the Upper Division, 

 occur 4 feet of hard, sandy and ferruginous limestones which are 

 regarded as in part the equivalents of the Northampton Beds. 



The Northampton Sand itself, " where fully developed, represents 

 the upper part of the zone of Am. Jurensis, the zone of Am. opalinus, 

 and portions of the zone of Am. Murchisonce." The exact horizon of 

 the overlying Lower Estuarine Beds is not quite clear. Judging 

 from the fauna there is good reason to suppose that the lower and 

 larger portion of the Lincolnshire Limestone is on or about the 

 horizon of the Oolite Marl. It is probable, however, that higher 

 beds succeed, and we cannot agree with the author in his suggestion 

 that the Great Ponton Beds may be merely a repetition of these in the 

 Little Ponton cutting. A study of the fauna is clearly in favour of 

 the view that the G-reat Ponton Beds are high in the series, many of 

 the fossils being Bathonian in character, whilst in the more northern 

 cutting some of the most characteristic fossils of the Oolite Marl 

 may be noted. As we proceed towards the Humber the repre- 

 sentative of the Northampton Sand has had the Yorkshire term 

 " Dogger " applied to it, whilst the Lincolnshire Limestone has been 

 divided into an upper series (the Hibaldstow beds) and a lower 

 series (the Kirton 15eds), though, so far as is known at present, 

 there is no marked pala^ontological distinction. 



The Great Oolite Series ( Bathonian) presents a marked contrast 

 to the preceding one in the comparative constancy of its Ammonite 

 species, which, moreover, are by no means numerous. The following 

 grouping is adopted. 



Cornbrash. Zone of Am. maerocephalus. 



! Forest Marble and Bradford Clay j Great Oolite Clay- 

 Great Oolite and j Great Oolite Limestone 

 FXrSaftf ' 1 ^PP^^ Estuarine Series 



