66 GASTEROPODA OF THE INFERIOR OOLITE. 



thing like the following sequence can be made out, commencing from the top. In 

 a shallow quarry north of Birdlip is a Nerincea-bed (p), immediately beneath the 

 Ragstone. In the Birdlip Hill section Nerincea occurs in the Oolite Marl (q), and 

 the same may be seen in the Oolite Marl of Leckhampton Hill. Again, both at Leck- 

 hampton and Birdlip, a third Nerincea-bed (r) occurs some twelve feet below the 

 Oolite Marl. When it is borne in mind that each of these beds represents, usually, 

 a slight line of erosion, and that probably other Gasteropoda have been procured 

 from them, the fixing of these lines in the Freestone series becomes a point of some 

 interest. The prevailing species on each of these three lines, or subhorizons, is 

 somewhat different. The bed r, towards the top of the Lower Freestones, is 

 distinguished by N. Cotteswoldice. These three beds belong to the Oolite Marl, or 

 middle Neringean-zone of the Cotteswolds, including in this term the bulk of the 

 Freestones. 



We must now consider the lower or Pea-grit Nerinasan-zone, as developed in 

 Crickley Hill. 



The principal object of the Profile of Crickley Hill (p. 67) is to exhibit the rela- 

 tions of the Pea-grit to the beds above and below. There is no difficulty about the 

 horizon, since Am. Murchisonce is not uncommon in the Pea-grit. The " semipiso- 

 lite," or equivalent of the Lower Limestone of Mr. Witchell, is very barren hunting 

 ground. The shell-beds towards the base of the section have not yielded any 

 notable quantity of Gasteropoda, but there are symptoms of a fauna similar to 

 that at Drympton on the borders of Dorset and Somerset. 



The really important bed in this Profile is the one containing long narrow forms 

 of Nerincea, of which sections are fairly numerous, and many smallish but rather 

 well-preserved Gasteropoda ; of these there are a few scattered throughout the 

 Pea-grit and Freestones generally. Two species of Nerita are to be found in 

 this bed. At the east end of the quarry face the line of the Nerincea-bed is 

 occupied by a small coral reef — the lower reef of the Cotteswolds. The great 

 expansion of the Pea-grit from about three feet at Nailsworth and Stroud to 

 upwards of thirty feet here is remarkable : in fact we are now entering on the 

 region of maximum sedimentation of the Cotteswolds, and it is a matter of consid- 

 erable interest for those who have traced the Inferior Oolite from its first appear- 

 ance in the cliffs of the English Channel, to reflect that a subordinate series in 

 the Murchisonce-zoiie at Crickley is nearly three times thicker than the entire 

 Inferior Oolite throughout some of the most fossiliferous exposures in Dorset- 

 shire. 



I will not dwell any further upon the Inferior Oolite as exhibited in the grand 

 semicircular escarpment from Leckhampton to Cleeve and farther north, but will 

 conclude this notice of its development in the Cotteswolds with a brief account 

 1 This is probably the same as the Swift's Hill bed (see Profile, p. 64). 



