﻿212 DE. A. VAT/GHAN ON THE PALJEONTOLOGICAL [May I905, 



horizontally) includes the Modiola-Zone (with Horizon a well 

 marked) and the greater part of the Cleistopora-Zone (only the 

 lowest portion of this zone being at the time of my visits at all 

 satisfactorily exposed). 



Still proceeding southward, it was found that the sides of the 

 road had, for the next 150 yards, been recently cut back, in such 

 a manner as to afford a good section through Horizon fi and the 

 lower portion of the Zaphrentis-Zone. 



A short distance farther south is a quarry in work (the ' Horse- 

 Eace ' Quarry), which contains beds belonging to the upper part of 

 the Zaphrentis-Zone. For the next 200 yards there are no 

 exposures that can be easily examined ; but, at the end of this 

 distance, there are large quarries in the thick oolite-band which 

 forms the middle portion of the Caninia-Zone. The remaining 

 500 yards of the road, to its junction with the Clevedon road, is 

 destitute of exposures. 



The thick band of oolite which forms the top part of the Failand 

 section is the equivalent of the Gully Oolite in the Avon section, 

 and, on account of its peculiar value for the manufacture of lime, 

 this oolite is quarried at several points of the Failand area ; it 

 consequently serves as a very valuable horizon, from which to 

 estimate the stratigraphical position of neighbouring exposures. 



Before, however, an isolated quarry in this oolite can be used 

 as a datum-level, it is imperative that the oolite in the quarry 

 should be definitely proved to be the oolite from the Caninia-Z<me, 

 and not the thick oolite-band which, throughout the Bristol area, 

 forms the middle part of the Seminula- Zone. 



The following diagnostic characters completely distinguish these 

 two oolitic bands : — 



(i) The Caninia-Oolite. 



At the base, Orthotetes (in association with C'honetes papilionacea) is 

 extremely abundant, and Syringothyris aff. laminosa is common. 



In the main part of the oolite fossils are uncommon, but Seminula, 

 Lithostrotion, and Productus aff. Cora are never found. 



(ii) Tbe Seminicla-Oolite. 



This oolite is usually prolific in fossils, and Seminula, Lithostrotion , 

 and Productus aff. Cora can always be found. 



C'honetes papiUonacea is, at the base of tbis oolite, quite as abundant as 

 it is beneath tbe Caninia-Oolite ; but Orthotetes is extremely rare. 



Above the oolite of the Caninia-Zone occur the ' Bellerophon- 

 Beds ' (Horizon <T), the most interesting palseontological horizon in 

 the Failand area. These beds are well shown in two isolated 

 quarries only ; the stratigraphical position of these quarries can, 

 however, be very accurately fixed by means of the Caninia-Oolite 

 which is worked near each of them. 



The first of these ' BelUrophon '-quarries lies just behind Failand 

 Inn, and about 100 yards south of the Clevedon road ; its position 

 is fixed by a shallow quarry, 350 yards west of Failand Inn, on the 

 south side of the Clevedon road. The shallow quarry contains the 

 lowest beds of an oolitic band, which is proved to belong to the 



