XV.] CAMBRIAN AND SILURIAN IN EUROPE. 371 



by the government geologists to the horizon of the Caradoc 

 proper or Bala group; nor was it until 1851 that their true 

 geological age and significance were made known. In that 

 year, Barrande, fresh from the study of the older rocks of the 

 continent, came to England for the purpose of comparing 

 the British fossils with those of the primordial zone, which 

 he had established in Bohemia and Scandinavia, and which 

 he at once recognized in the Lingula flags of Sedgwick and 

 in the black schists at Malvern ; both of which were char- 

 acterized by the presence of the genus Olenus, and were 

 referred to the horizon of his Etage C. This important con- 

 clusion was announced by Salter to the British Association at 

 Belfast in 1852. (Eep. Brit. Assoc., abstracts, p. 56, and 

 Bull. Soc. Geol. de Fr. (2), XVI. 537.) [The black schists of 

 Malvern, and the underlying greenish beds known as the 

 Hollybush sandstones, are by Hicks regarded as the equivalents 

 respectively of the Dolgelly and Festiniog divisions of the Lin- 

 gula-flags. (Proc. Geologists, Association, Vol. III. No. 3.)] 

 The palaeontological studies of Salter, while they confirmed 

 the primordial character of the whole of the great mass of strata 

 which make up the Middle Cambrian or Festiniog group of 

 Sedgwick (consisting of the Lingula flags and the Tremadoc 

 slates), led him to propose several subdivisions. Thus he 

 distinguished on palseontological grounds between the upper 

 and lower Tremadoc slates, and for like reasons divided the 

 Lingula flags into a lower and an upper portion. For the 

 discussion of these distinctions the reader is referred to the 

 memoirs of the Geol. Survey (III. 240-257). Subsequent 

 researches led to the division of the original Lingula flags into 

 four parts, an upper, middle, and lower, to which the names 

 of Dolgelly, Festiniog, and Maentwrog were given by Mr. 

 Belt in 1867, and a fourth, consisting of the basal beds, which 

 had been already separated in 1865 by Salter and Hicks, with 

 the designation of Menevian, derived from the ancient Roman 

 name of St. David's in Pembrokeshire.* It was here that, in 



[* The researches of Mr. Belt on the Lingula Flags appeared in 1867. 

 (Geological Magazine, Vol. IV. 483 and 536, and Vol. V. 5.) He included 



