372 CAMBRIAN AND SILURIAN IX EUROPE. [XV. 



1862, Salter found Paradoxides with Agnostus and Lingula in 

 fine black shales at the base of the Lingula flags, resting con- 

 formably on the green and purple grits of the Lower Cambrian 

 or Harlech beds. The locality was afterwards carefully studied 

 by Hicks, and it was soon made apparent that the genus Para- 

 doxides, both here and in North Wales, was confined to a 

 horizon below the great mass of the Lingula flags ; which, on 

 the contrary, are characterized by numerous species of Ole- 

 nus. These lower or Menevian beds are hence regarded by 

 Salter as equivalent to the lowest portion of the Etage C of 

 Barrande. 



Beneath these Menevian beds there lies, in apparent con- 

 formity, the great Lower Cambrian series, frequently called the 

 bottom or basement rocks by the government surveyors ; rep- 

 resented in North Wales by the Harlech grits, and in South 

 Wales, near St. David's, by a similar series of green and purple 

 sandstones, considered by Murchison, and by others, as the 

 equivalent of the Harlech rocks. They were still supposed to 

 be unfossiliferous until in June, 1867, Salter and Hicks an- 

 nounced the discovery in the red beds of this lower series, at 

 St. David's, of a Linguleila, very like L. ferruginea of the 

 Menevian. (Geol. Jour., XXIII. 339 ; Siluria, 4th ed., 550.) 

 This led to a further examination of these Lower Cambrian 

 beds, which has resulted in the discovery in them of a fauna 

 distinctly primordial in type, and linked by the presence of 

 several identical fossils to the Menevian ; but in many respects 

 distinct, and marking a lower fossiliferous horizon than any- 

 thing known in Bohemia or in Scandinavia. 



The first announcement of these important results was made 



under the name of Upper Cambrian the Tremadoc rocks with the Lingula 

 flags proper, which he divided in descending order into three parts, Dolgelly, 

 Festiniog, and Maentwrog ; while he suggested the union of the basal beds, 

 (previously separated under the name of Menevian,) with the underlying 

 Harlech and Bangor rocks as Lower Cambrian. These divisions of Belt are 

 now recognized by Hicks. It will be recollected that the whole of the 

 Lingula flags were originally included in his Festiniog group by Sedgwick. 

 All of these rocks are inverted in the vicinity of Dolgelly, the apparent 

 succession in descending order being Festiniog, Dolgelly, Tremadoc, and 

 Arenig.] 



