﻿Vol. 6 I.] SEQUENCE IN THE BRISTOL AREA. 253 



Dr. Smith Woodward makes the following remarks on the fish-teeth 

 and spines found in the Oreton Limestone : — 



' The fine teeth of Orodus ramosus and Sandalodus Morrisi, and the fin- 

 spines named Ctenacanthus major and Ct. sulcatus, are identical with the fossil 

 teeth and spines occurring in the Black Bock at Olifton, Bristol; but, so far as 

 I haye observed, there is no similarity between the Oreton fish-fauna and that 

 met with in the bone-bed of the Lower Limestone-Shales at Clifton.' 



In the Black-Hock Quarry at Clifton, fish-teeth and spines of the 

 above types have been found at several levels, from the "base up to a 

 little beyond the middle of the quarry ; but the beds in which they 

 are most abundant occur at the top of this range. This may be 

 expressed in faunal units, by saying that the teeth and spines found 

 at Oreton occur in the Bristol area at any point in the Zaphrentis- 

 Zone, from the middle of Z x up to nearly the top of Z 2 . Their 

 maximum occurs nearly at the top of Z 2 , above the maximum of 

 Schizophoria resupinata and Cliothyris glabristria, and just below 

 that of Syringothyris cuspidata. 



I devoted a day to collecting in the Oreton Quarry, with the 

 result that a specimen of Orodus ramosus was found below beds 

 containing the following fossils : — 



Syringothyris cuspidata (very abundant). , Orthotetes crenistria (common). 



Syringothyris aff. laminosa. j Eeticularia aff. lineata. 



Camarotcechia mitcheldeanensis (very j Productus cf. Martini. 



abundant). ! Productus aff. pustulosus. 



Cliothyris glabristria. j Michelinia sp. 



Cliothyris Boyssii (mut.). j Zaphrentis aff. Phillipsi. 



If, now, the range-diagrams (Pis. XXVIII & XXIX, facing 

 pp. 244 & 246) be consulted, it will be seen that the only possible 

 position in which a vertical line can be ruled so as to cut the 

 ranges of all the fossils cited above it, must lie within the 

 Zaphrentis-Zoiae, and (in order to cut the ranges of Michelinia and 

 Syringothyris aff. laminosa) the line must be drawn in Z 2 . The 

 form of Productus cf. Martini and the abundance of Camarotcechia 

 mitcheldeanensis would suggest that the line must be drawn low 

 down in Z 2 . 



I think it may be justly claimed that the two methods of 

 zoning lead to identical results, and that the zonal position of the 

 ' Clee-Hill Marble ' is fixed beyond the possibility of question. 



In a clay just above the limestone on the south side of the Glee 

 Hills, 1 Syringothyris aff. laminosa is fairly common, and a single 

 specimen of Schizophoria resupinata was found. This clay conse- 

 quently occurs also in Z 2 . 



!.| tThe overlying beds are of great interest, but the partial absence 

 of fossils forbids their reference to any definite horizon. 



The short distance at which the ' Millstone-Grit ' occurs above 



1 I had the great advantage of the help of Mr. E. Dixon and Mr. O. T. Jones, 

 in examining this portion of the Clee-Hill outcrop. 



