390 MR. S. S. BTJCKMAjST ON THE BAJOCIAN [Aug. 1895, 



valley of the Chelt, as far as it runs, forms a convenient line of 

 demarcation ; and the geological feature is the almost complete 

 absence of the Harford Sands. Continuing eastwards from the 

 valley of the Chelt the northern boundary might follow the Oxford 

 road from Andoversford as far as Little Barrington, where it might 

 turn into the valley of the "Windrush. 



The Northern Cotteswolds would extend from this line of demar- 

 cation to the northern prominences of the Cotteswolds, including 

 Ebrington Hill. The district is characterized by the development 

 of the Harford Sands. 



Although these divisions are unequal in geographical extent, 

 their interest does not depend on that factor. In the Mid-Cottes- 

 wolds lie some of the best developments of what is called ' Inferior 

 Oolite,' the Pea-grit being especially noticeable. 



Intervening Beds. — This term is proposed, merely for brevity, in 

 connexion with the present paper to denote all beds lying between 

 the Upper Freestone and the Upper Trigonia-gni. 



Bajocian Denudation. — This term is used for denudation which 

 happened between the hemerse Garantiance-Sauzei, and was com- 

 pleted before the strata of the Garantiance hemera were deposited. 



Buckmani-gr^. — With apologies I introduce a term which has 

 already obtained colloquial recognition. It is intended to designate 

 a series of strata which are sandy at Leckhampton Hill and lie 

 between the Gryphite and Lower Trigonia-grits. Frequently they 

 have been overlooked entirely, otherwise they were classed as u 

 portion of the Gryphite-grit ; but it is advisable to restrict that term 

 to some essentially gryphseiferous beds at Leckhampton, and to their 

 contemporaries whether gryphaeiferous or not. 1 The Bucfanani-grit 

 is especially noted for the occurrence of Terebratula Buckmani and 

 4 Terebr. BucJcmaniana.' 2 These are the most noticeable and most 

 easily recognized fossils ; they seem to be particularly confined to 

 the grit in question. I know no other fossils which would so 

 appropriately give their names for this purpose. 



~W itch eUi &-grit. — This term is to denote a series ofragstones 

 above the Notgrove Oolite, yielding angustumbilicate Witchellice 

 and other Sonnininse, as well as Terebratula Wrighti, Davidson. 



Non-sequential Strata. — The word ' unconformable ' is used in 

 two senses, and little trouble is taken to distinguish between them. 

 Not only is it employed when strata are deposited across the upturned 

 edges of earlier rocks, but it is also pressed into service when there 

 is simply a deficiency in the full sequence, although the strata may 

 be so far conformable that their planes may be practically parallel. 

 It seems necessary to make a distinction, thus : — 



1 It may be noticed that the absence of a Gryphcea in other localities would 

 not be evidence against contemporaneity with the Gryphite-grit of Leckhamp- 

 ton. Like the oyster, the Gryphcea no doubt was very dependent on local 

 conditions, and too much sediment would be detrimental to the hatching of 

 spat or thriving of the young. 



2 But see Appendix to Part III. 1 c, p. 454. 



