112 Classification and Nomenclature of the 



It proved, however, that the rocks to the west of the Llan- 

 deilo valley were newer, and not older than the flags; that 

 in fact the Llandeilo flags werenotabove the Cambrian system, 

 but an integral part of it. But, instead of adding the narrow 

 belt of country occupied by these flags to the Cambrian system, 

 Sir It. Murchison had wished to convert the whole breadth of 

 the Cambrian region into Silurian. Prof. Sedgwick then re- 

 ferred to the section of the Malvern strata, as determined by 

 Prof. Phillips ; he contended that the Caradoc sandstone and 

 conglomerate of this section belonged in reality to the Wenlock 

 series, and proposed for it the name of " May-hill sandstone." 

 The underlying black shales and " Hollybush sandstone," 

 of Prof. Phillips he regarded as the true Caradoc sandstone, be- 

 longing to the Cambrian system. Prof. Sedgwickfurther endea- 

 voured to shew, by sections and lists of fossils, that the Silurian 

 May-hill sandstone existed in a distinct form in the typical dis- 

 trict of the Caradoc sandstone. With this correction the Cam- 

 brian system would include the lower Silurian of SirR. Mur- 

 chison. The distinctness of the Cambrian or Lower Silurian 

 from the Upper Silurian was admitted on fossil evidence ; Mr 

 Barrandehad found only 6 per cent, of fossils common to the two 

 systems in Bohemia, and Mr Hall only 5 per cent, in America. 

 In Westmoreland the per-centage was only 3%. Of 324 

 species in the Cambridge Museum, not 15 per cent, were 

 common to the two systems, including all the doubtful cases, 

 and the real number was probably not above 5 per cent. 

 Professor Sedgwick then read a letter from Professor Rogers 

 in America, expressing his approval of this nomenclature, 

 and his conviction that it would be eventually be adopted ; he 

 also entered upon an explanation of the manner in which his 

 various papers on this subject had been published in the 

 Journal of the Geological Society, as it had been supposed 

 that he himself had abandoned the term Cambrian at one 

 time, whereas the alteration had been made in his paper 

 by a former President (Mr Warburton) of the Society, with- 

 out his knowledge. 



Mr Hopkins, late President of the Geological Society, ex- 

 plained some of the circumstances referred to by Professor 

 Sedgwick, and expressed a strong conviction that the Pro- 



