XV.] CAMBRIAN AND SILURIAN IN EUROPE. 383 



hills, on the western flanks of which, as already mentioned, 

 the Lingula flags are represented by about 500 feet of black 

 shales with Olenus, underlaid by 600 feet of greenish sand- 

 stones containing traces of fucoids, with Serpulites and an 

 Obolella. It is not improbable, as suggested by Barrande and 

 by Murchison, that these 1,100 feet of strata represent, in this 

 region, the great mass of the Lingula flags ; and, we may add, 

 perhaps, the whole series of Lower Cambrian strata, which in 

 Caernarvon and Pembroke underlie them [see page 371] ; since 

 these sandstones of Malvern, like those of St. David's, rest upon 

 crystalline schists, and are in part made up of their ruins. 



These crystalline schists of Malvern, which are described by 

 Phillips as the oldest rocks in England, and by Mr. Holl are 

 conjectured to be Laurentian, seem from the descriptions of 

 their lithological characters to resemble those of Caernarvon 

 and Anglesea, with which they are, by Murchison, regarded as 

 identical. The crystalline schists of these latter localities are, 

 by Sedgwick, described as hypozoic strata, below the base of 

 the Cambrian. Murchison, however, in the first edition of his 

 Siluria, adopted the suggestion of De la Be'che that they them- 

 selves were altered Cambrian strata. In fact, they directly 

 underlie the Llandeilo rocks, and were apparently conceived by 

 Murchison to represent that downward continuation of these 

 upon which he had insisted. This opinion is supported by 

 ingenious arguments on the part of Ramsay. (Mem. Geol. 

 Survey, III. Part II., passim.} I am, however, disposed to 

 regard them, with Sedgwick and Phillips, as of pre-Cambrian 

 age, and to compare them with the Huronian series of North 

 America, which occupies a similar geological horizon, and with 

 which, as seen in northern Michigan, and in the Green Moun- 

 tains, I have found the rocks of Anglesea to offer remarkable 

 lithological resemblances. 



It may here be noticed that the gold-bearing quartz veins in 

 North Wales are found in the Menevian beds, and also, accord- 

 ing to Selwyn, throughout the Lingula flags. These fossilifer- 

 ous strata at the gold-mine near Dolgelly appear in direct con- 

 tact with diorites and chloritic and talcose schists, which are 



