﻿182 DK. A. VAT7GHAN ON THE PAL2E0NT0L0GICAL [May I905, 



4 On Insoluble Residues obtained from the Carboniferous-Lime- 

 stone Series at Clifton/ 1 and it is with his lithological divisions 

 that I have mainly correlated the palajontological zones suggested 

 in this paper. 



To the late Mr. W. W. Stoddart 2 we owe the first attempt to 

 compile a list of the fossil contents of the beds in the Avon Section. 

 I have drawn up a complete analysis of his observations, so far 

 only as the Corals and Brachiopods are concerned ; this will, for 

 convenience, follow immediately upon the detailed account of my 

 own observations on the Avon section. 



For my purpose, it is obvious that the essential desiderata are 

 good exposures, the relative stratigraphical position of which is 

 unquestionable. Exposures which satisfy these two conditions are 

 to be found in several parts of the Bristol area, and, from them, 

 the determination of the faunal sequence is merely a matter of 

 accurate observation and careful tabulation. 



Since every fossil that is recorded in the following lists was 

 noted down at the instant at which it was observed, while all 

 specimens which presented any difficulty in determination were 

 extracted as completely as possible and carefully re-examined 

 at leisure, I may claim that these lists are absolutely reliable, 

 provided that each name presents exactly the same 

 idea to those who read it, as it does to me in writing 

 it. 



This is always a very necessary reservation to bear in mind, in 

 the interpretation of lists of fossils from the Carboniferous Lime- 

 stone. The most familiar specific names usually cover so many 

 mutations and varieties, that they convey no exact information, and, 

 in consequence, comparisons instituted, in reliance on such lists, 

 are apt to be very unconvincing. The indefiniteness of the well- 

 known specific names was well pointed out by Prof. Watts, in 

 his presidential address to the Geological Section of the British 

 Association, at the Southport meeting in 1903. 3 



In order to secure the requisite deriniteness, I have appended a 

 series of photographs (Pis. XX1I-XXVI) which not only illustrate 

 the new specific names that I hare here introduced for the first time, 

 but also convey the precise sense in which some of the well-known 

 specific names are employed in this paper. With this addition, I 

 believe that I may fairly claim for this paper : — 



(1) That, it is an accurate record of the faunal sequence throughout the 



Bristol area. 



(2) That, by means of the plates, the majority of the specific names 



convey the precise meaning which they are intended to bear. 



1 Quart. Journ. Geol Soc. vol. xliv (1888) p. 186. 



2 Proc. Bristol Nat Soc. n. s. vol. i (1875) p. 313. 

 Rep. Brit. Assoc. 1903 (Southport) p. 643. 



