ANNIVERSARY ADDRESS OF THE PRESIDENT. 



71 



research, however, was due to Dr. Hicks, whose intimate acquaint- 

 ance with the area and knowledge of the fauna of the Cambrian 

 and Silurian rocks enabled him to add largely to the palaeontology 

 of the district. The authors described the great series of red, purple, 

 green, and grey rocks below the fossiliferous grey Menevian beds. 

 The history of these variously coloured sandstones, as revealed by 

 the researches already made in them, has an important bearing 

 upon our knowledge of the distribution of life through the Cambrian 

 and Silurian series of North Wales, with which they must be 

 correlated, the St.-David's series yielding a fauna not yet known 

 in Monmouthshire, Caernarvonshire, or Montgomeryshire, or beneath 

 the Menevian and Lingula-flags of North Wales, which contain 

 organic remains older than, and different in species from any hitherto 

 discovered in Britain. The underlying Cambrians repose upon a 

 conglomerate, composed of quartz and other pebbles cemented in a 

 purple or red arenaceous matrix, which occurs on both sides of the 

 so-called Pre-Cambrian ridge or axis. That this quartziferous, 

 metamorphosed, crystalline, and unconformable mass underlies and 

 is older than the whole series of the Lower Cambrian rocks of that 

 area is certain ; and, as such, it is the key to the physical structure 

 of the ancient headland of St. David's. Subsequent research by 

 Hicks has determined that this extensive and exposed Pre-Cambrian 

 area is composed of three distinct groups of metamorphosed sedi- 

 mentary rocks of different ages, and having different or discordant 

 bearings or strikes*. Higher still, and also unconformably, succeed 

 the rocks of the Harlech or Longmynd group, which lie both to the 

 east and west. Until the Longmynd, Harlech, and Menevian fauna 

 was discovered and worked out at St. David's, and the last named 

 subsequently developed in North Wales, the lowest sedimentary 

 rocks of Britain then known were believed to be almost devoid of 

 life or "barren in fossils." Now, however, a remarkable fauna has 

 rewarded the researches of many distinguished labourers, and the 

 two areas have been carefully compared and correlated. Consider- 

 able differences exist, of which the causes are as yet unknown ; 

 much has yet to be done in the palaeontology of both these classical 

 districts. The non-discovery or absence of the genus Olenus in the 

 Menevian and Lingula-flags or primordial rocks of St. David s is 

 singular, and at present inexplicable. The genus is abundantly 

 represented in both the Lower and Upper Lingula-flags of North 

 Wales, where no less than 12 species are known, 4 in the lower 

 division and 8 in the upper; and 4 distinct forms (viz. 0. bisulcatus, 

 0. scarabceoides, 0. humilis, and 0. pauper) occur in the Upper Lin- 

 gula-flags of Malvern, overlying the Hollybush sandstones. The 

 species 0. scarabceoides (0. spinulosis, Phill.) is found also in the 

 Upper Lingula-flags of Carreg-Wen, west of Portmadoc. 



Comparison of the earliest known faunas in Europe and America 

 with that of St. David's shows conclusively that they are identical as 

 to age or time of deposition and in genera also. This Angelin has 

 * See p. 56 et seq, 



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