490 J. E. MAEE AND T. EOBEETS ON THE 



§ 4. Conclusion. 



We have endeavoured, in this paper, to establish the succession 

 in the district under consideration. That certain difficulties are not 

 yet cleared up is admitted. Our inability to discover any section 

 showing normal Sholeshook limestone resting upon normal Eobeston- 

 Wathen limestone is unfortunate. In separating these stages from 

 each other, we are influenced by the lithological and palseontological 

 differences between the two deposits, and by comparison with 

 similar beds in other areas. But for this, we should be disposed to 

 look upon the Kobeston-Wathen limestone as a local development 

 of the Sholeshook limestone. We may note, however, that there 

 are many places in the district where one or more of the limestones 

 can be satisfactorily proved to have been crushed out. 



As already explained, also, the relation of the conglomerate to 

 the succeeding beds requires further study. 



These minor difficulties have been encountered when studying 

 portions of the sequence which are typically developed elsewhere. 

 As they do not greatly affect our establishment of the sequence in 

 this area, and as other difficulties would probably arise upon further- 

 exploration, the announcement of our results might be indefinitely 

 postponed, and we therefore venture to bring our work before the 

 Society, in the belief that what we have done will prove sufficient 

 to furnish a clue to the solution of a very interesting question, viz. 

 the nature of the foldings which have affected the district. 



EXPLANATION OF PLATE XV. 



Fig. 1. Geological Sketch-Map of the neighbourhood of Haverfordwest. The^ 

 map, based on that of the Geological Survey, is simply intended as a 

 sketch-map, shovping the general distribution of the beds ; and the 

 boundaries in many places are only approximately correct. The- 

 Eedhill beds and Slade beds have been represented by the same 

 sign, as vre have not traced the boundary between them oyer the 

 whole district. The I)icranogra])tus-shales of Grondre and Longford 

 may extend further east than represented. 



2. Section in Quarry south-east of Trefgarn Bridge. 



3. Section through Eobeston Wathen. 



4. Section in the Lane north of Prendergast Church. 



5. Diagram-section along the Railway from Haverfordwest Station to 



north of Orundale. 



DiscirssioN. 



The Peesident expressed his pleasure at seeing that such ad- 

 mirable work had been done by Cambridge geologists. 



Dr. Hicks stated that the Authors had entirely confirmed his 

 views that the rocks of Eoch Castle and Trefgarn which he had 

 referred to the Archaean were not, as believed by the Geological 

 Survey, intrusive rocks penetrating Lower-Silurian strata. The 

 recognition of the important fact that these are of Pre-Cambrian 

 age was absolutely necessary before the geology of the area could 



