﻿254 DR. A. VATTGHAN ON THE PAL^ONTOLOGICAL [May 1905, 



the clay already mentioned renders it probable that the entrance of 

 the grit-facies was even earlier in the Clee-Hill area than in the 

 Mitcheldean district.] 



(t) The South-Wales Outcrop. 



[I have recently had the opportunity of studying the faunal 

 sequence in both the ' North and South Crops ' ; the former in the 

 neighbourhood of Kidwelly, and the latter in the district around 

 Tenby. Mr. Ernest Dixon, B.Sc, F.G.S., of H.M. Geological 

 Survey, very kindly acted as guide, and, as he had already made 

 out the stratigraphical relationship of the different exposures, I was 

 able to test the value of the faunal sequence without any waste of 

 time. 



Nothing could be more striking than the remarkable agreement 

 of the faunal sequence in this area with that in the Bristol and 

 Mendip areas. Even the rarest forms have been found at precisely 

 the same level in the two regions. Eor example, a single specimen 

 of a bryozoan (' C7icetetes radians ' ?) has been found about the 

 middle of S 2 in the Avon section, and exactly the same fossil occurs 

 in the same position near Tenby. 



(a) The e North Crop' in the Neighbourhood of Kidwelly. 



The Cleistopora-Zone and Horizon (3 are typically developed in 

 the ' Black Eocks' near Llanstephan. 



No exposures in the Zaphrentis- or Synngothyris-Zones were 

 observed. 



The Seminula-fteiies is typically displayed in the large Ean 

 Quarries, and here exactly the same forms occur at the same levels 

 as in the Bristol area. Eor example, Caninia cylindriea, mut., 

 Lithostrotion basaltiforme, var., Productus d, Lithostrotion Martini, 

 and Seminula ficoidea characterize S 1 . Productus an 2 . Cora 

 (mut. S 2 ) occurs in S 2 with its usual associates, and here also 

 Alveolites is not uncommon, together with Cyrtina carbonaria, 

 which I have met with at the same level in the Wye quarries 

 north of Chepstow, but have not yet recognized in the Bristol 

 area. 1 



The lower part of D 1 was not made out. The upper part of D l 

 is well shown, and exactly resembles the Sodbury development. 



D 2 is splendidly displayed, and contains the characteristic forms. 



Horizon e is here a calcareous stratum, and abounds in Productns 

 aff. scabriculus (cf. Pr. costatus), the form being identical with that 

 found in the Avon section. Hence, the entrance of the ' Millstone- 

 Grit' phase is, zonally, somewhat later than in the Bristol area, 

 where Horizon e occurs within the base of the Grit. 



1 Cyrtina carbonaria is, however, very abundant at the base of S 2 in the 

 Weston area, where a bed crowded with this fossil was pointed out to rue by 

 Mr. Sibly. It has also been recently discovered at Wickwar (see above, p. 239). 



