Vol. 69.] BATHONIAN ROCKS OF THE OXFORD DISTRICT. 493 



as is shown by the fact that water is always held up in ponds. 

 Near this, in the railway-cutting the following section occurs 1 : — 



Thickness in feet. 



Cornbrash, yielding Pseudomonotis echinata (Sow.), Homomya gibbosa 

 Sow., GresslyaperegrinaPhil., Modiola imbricata Sow., Pectenvagans 

 Sow., Pholadomya deltoidea Sow., Pleuro-mya securiformis Phil., 

 Terebratula intermedia Sow., Ornitliella obovata (Sow.), and Py gurus 

 ■michelini Cott about 3 



Olay 8 



Hard, grey, oolitic limestone 1 Forest \ . 



Flaggy brown oolite j Marble J 



Clay 2| 



White limestone containing Nenncea (Great Oolite). 



It is unfortunate that all the other exposures round Islip are 

 now filled in : since, judging from the list given by Phillips, who 

 mentions no less than sixty-five species from Islip, the exposures 

 have been very fossiliferous. 2 



(d) Oxford Portland-Cement Works, Kirtlington. 



The Cornbrash here forms a subsoil about 4 feet thick ; it is of 



the usual character, yields the usual fossils (see p. 501), and calls 



for no special note. 



The Forest Marble is only 17 feet thick, and is separated from 



the Cornbrash by a 2-inch band of clay ; the following is the 



generalized section : — 



Thickness in feet inches. 



Bed a. Marly clay 2 



Bed b. Horizontally-bedded compact marl 1 9 



Bed c. Marly clay 1 



Bed d. False-bedded limestone 4 6 



Bed e. Marly clay 3 



Bed /. False-bedded limestone 2 6 



Bed g. Marl with limestone-nodules and ' race' 1 9 



Bed/*. Compact marly limestone , 1 



Bed i. Compact oolitic limestone 6 



Bed j. False-bedded limestone 1 



17 2 



Very few fossils occur, and, except for the bottom 18 inches, the 

 limestones are all of a marly character. 



Great Oolite. Thickness in feet inches. 

 fBed 1. 'Fossiliferous Ci-eam - Cheese Bed' (locally be- 

 coming oolitic and containing corals) 2 10 



Bed 2. Green clay (brown at the base, where it contains 



~| lignite) 3 



o<jBed3. Shelly limestone 1 4 



° I Bed 4. Green clay 2 8 



W | Bed 5. Coarse, brown, marly limestone 8 



| Bed 6. Green clay 4 



( Bed 7. * First Terebratula Bed ' 1 



1 A. H. Green, ' Geology of the Country round Banbury, &c.' Mem. Geol. 

 Surv. 1864, p. 35. 



2 ' Geology of Oxford, &c.' 1871, pp. 239 et seqq. 



