XV.] CAMBRIAN AND SILURIAN IX EUROPE. 373 



to the British Association at Norwich in 1868. Further details 

 were, however, laid before the Geological Society in May, 

 1871, by Messrs. Harkness and Hicks, whose paper on The 

 Ancient Rocks of St. David's Promontory appears in the 

 Geological Journal for November, 1871. (XXVIII. 384.) 

 The Cambrian sediments here rest upon an older series of 

 crystalline stratified rocks, described by the geological sur- 

 veyors as syenite and greenstone, and having a northwest 

 strike. Lying unconformably upon these, and with a north- 

 east strike, we have the following series, in ascending order : 

 1. Quartzose conglomerate, 60 feet ; 2. Greenish flaggy sand- 

 stones, 460 feet ; 3. Red flags or slaty beds, 50 feet, containing 

 Lingulella ferruginea, besides a larger species, Discina, and 

 Leperditia Cambrensis ; 4. Purple and greenish sandstones, 

 1,000 feet ; 5. Yellowish-gray sandstones, flags, and shales, 

 150 feet, with Phttonia, C onocoryphe, Microdiscus, Agnostus, 

 Theca, and Protospongia ; 6. Gray, purple, and red flaggy sand- 

 stones, with most of the above genera, 1,500 feet ; 7. Gray 

 flaggy beds, 150 feet, with Paradoxides ; 8. True Menevian 

 beds, richly fossiliferous, 500 feet. The latter are the probable 

 equivalent of the base of Barrande's Etage C, and at St. David's 

 are conformably overlaid by the Lingula flags ; beneath which 

 we have, including the Menevian, a conformable series of 

 3,370 feet of uncrystalline sediments, fossiliferous nearly to the 

 base, and holding a well-marked fauna distinct from anything 

 hitherto known in Great Britain or elsewhere. 



The Menevian beds are connected with the underlying strata 

 by the presence of Lingulella ferruginea, Discina pileolus, and 

 Obolella sagittatis, which extend through the whole series; 

 and also by the genus Paradoxides, four species of which occur 

 in these lower strata ; from which the genus Olenus, which 

 characterizes the Lingula flags, seems to be absent. To a large 

 tuberculated frilobite of a new genus found in these lowest 

 rocks the name of Plutonia Sedgwickii has been given. Hicks 

 has proposed to unite the Menevian with the Harlech beds, 

 and to make the summit of the former the dividing line be- 

 tween the Lower and Middle Cambrian, a suggestion which 



