Correspondence — The Rev. Prof. Blake. 525 



completeness. Thus a record of the Echinoderms which does not 

 include Cotteau's Eocene Echinides (Pal. Franc), de Loriol's Crinoides 

 Jurassiques, and Echinides cretaces du Portugal, Pomel's Paleonto- 

 lo<>ie de l'Algerie; nor mentions Seune's discoveries in the Pyrenees, 

 White's in Brazil, or de Loriol's additions to the fauna of Angola, 

 cannot be for a moment compared with M. Gauthier's summary of 

 the group. Nevertheless, complete though the work is, there are 

 some few omissions; thus while a paper on the Mauritius Bryozoa, 

 which is solely of zoological interest, is recorded and summarized, 

 the Sarrasins' important work on the Echinothuridae is not men- 

 tioned, though of especial interest to palaeontologists. The list of 

 abbreviations, which was quite inadequate in previous volumes, 

 lias disappeared entirely from the present, and one is left to guess 

 what is meant by the G.F.F. and the Jahrbuch G.R.A. : the brevity 

 in such cases strikes one as unnecessary in contrast to those in which 

 such words as Rendiconti are printed in full. In many cases there 

 is a lack of uniformity in the abbreviations, and the same work is 

 quoted differently on the same page. Sometimes no reference is 

 given to the place of publication of a paper, as in Sansoni's " Note 

 di mineralogia italiana" (1S55). The frequent absence of cross- 

 references in the case of joint authorship is also unfortunate. 



In spite of such slips and omissions, it must be admitted that the 

 Annuaire Geologique Universel is the most complete and reliable 

 guide to current geological and palaentological literature. J. W. G. 



COEEESPOITDEUCE 



THE CAMBRIAN CONGLOMERATE OF ST. DAVIDS. 



Sir, — The statement to which Dr. Hicks objects may be some- 

 what loosely worded, but if the words used be clearly defined it 

 is not very far from the truth. In speaking of a conglomerate we 

 distinguish " pebbles " and " matrix." When the word '• fragment " 

 is used, it is generally supposed to refer to the former; the latter, 

 however, may also contain fragments of smaller size ; and with the 

 exception of certain true pebbles from Whitesand Bay and Kamsey 

 Island, all the fragments referred to by Dr. Hicks come under this 

 category. The conglomerate of Ramsey Island is truly " composed " 

 of felsite pebbles, but there is no proof of its age. Elsewhere the 

 conglomerates may contain fragments of various rocks, but they are 

 mainly composed of quartz pebbles. My statement is a re-echo of 

 the words of Prof. Hughes that "he did not believe that the little 

 particles of felspathic rock in the grit would carry conviction." 

 Indeed in any case it is very extraordinary that though the present 

 beach at Chanter's Seat and elsewhere is strewn with large granite 

 pebbles from the neighbourhood, the older conglomerate is so free 

 from them, and so full of quartz from somewhere else. This fact, 

 which thus stated can scarcely be denied, tends to minimize the 

 interval between the conglomerate and the underlying rocks, and 

 the presence of small fragments of similar rocks which are abundant 

 in Precambrian areas does not do much in the contrary direction. 



Sept. 20, 1890. J. E. Blake. 



