﻿266 DE. A. VAUGHAN ON THE PAL^ONTOLOOICAL [May I905, 



To Mr. T. F. Sibly I am deeply indebted for continuous help in 

 the field-work, and without his assistance the examination of the 

 Bristol area would have been far less comprehensive than it is. 



I have to thank Mr. W. H. Wickes and Mr. L. Richardson for 

 some of my finest specimens. 



To Mr. J. W. Tutcher I owe the excellent photographs (reproduced 

 in Pis. XXII-XXVI) illustrating this paper, to the preparation of 

 which he has devoted so much care. Several of the photographed 

 specimens belong to his fine collection. 



I have also to thank the Director of H.M. Geological Survey and the 

 Committee of the Bristol Museum, for permission to photograph 

 specimens in the Jermyn-Street and Bristol Museums. 



I cannot sufficiently thank Mr. L. L. Belinfante, M.Sc, for the 

 very great trouble which he has taken in editing an extremely- 

 technical paper. 



VII. Notes on the Coeals and Beachiopods eefeeeed to 



IN THE FaTJNAL LlSTS. 



The object of these notes is merely to explain the faunal lists, 

 by indicating the interpretation which I intend each name to bear. 

 For this purpose, no historical research into the priority of names 

 is necessary, nor is it absolutely essential that the names should 

 cover the original type. So long as the explanation and references, 

 here given, are sufficient to particularize the form which each name 

 is intended to denote, my object will have been completely achieved. 



On the other hand, I have endeavoured to employ each name 

 in what I believe to be the meaning attached to it by accepted 

 authorities, so that reference to easily-accessible figures is, in most 

 cases, sufficient. For example : Froductus Cora is employed in the 

 sense in which I believe it to have been used by Davidson, not- 

 withstanding the fact that it is doubtful whether the original type 

 of the species is very closely allied to the forms here intended. 



In the case of important stratigraphical forms which only bear a 

 limited resemblance to forms already figured, I have merely indexed, 

 the forms by the addition of the letters 6, 0, \p to the generic name. 

 This method has the advantage of conveying definite information, 

 without asserting relationship to somewhat similar forms the 

 position of which, on the chronological scale, is at present unknown. 

 Should both the Bristol form and the one already figured, to which 

 it bears a certain resemblance, be found, later, to occupy the same 

 chronological position, it will be rendered probable that both are 

 mere local variants of the same gens, and they can then receive 

 the same name. 



I have followed the same plan in cases where I consider that 

 very distinct forms have been included under the same name, and 

 where I wish to indicate only one of the forms so included. 



