68 PKOCEEDINGS OF THE GEOLOGICAL SOCIETY. 



( ^00 ft' } Sandstones an d shales, with Orthis Hicksii &c. 

 ^group ^ ^35(f ft' } ^ a f s an d suites, with Paradoxides Davidis. 

 \ 30^ ft' } ® Te J na S s ? with Paradoxides Hicksii &c. 



Y5O ft' } ^ rc ^ roc -^ s ' w ith Paradoxides aurora &c. 

 Solva Middle f ® re y' P ur pl e > an d re d rocks, with Paradoxides solvensis 

 grout) 1500 ft' I (Hicks, MS.), ConocorypJie solvetisis, &c, also Eophy- 

 ° *■ ' I , tow and large fucoids. 



I Lower, f Yellowish grits, sandstones, and flags, with Paradoxides 

 { 150 ft. \ Har/messii, Plutoniq Sedgwickii, &c, also Eophyton. 



\ ^00 ft' j ^ >ur P^ e sandstones, with Annelids. 



Caerfai ■ Middle f-^ ec ^ shales an d schists, with Leper ditia cambvensis, 



n-™ ™ \ rr\ a ' 1 Linqulella yrimceva, Piscina caerfaicnsis (Hicks,, 



group. ou It. ^ Mg ^ &c 



I Lower, f Conglomerates and green flaggy sandstones, with An- 

 ( 520 ft. j nelids. 



Below the Caerfai group in South Wales, at St. David's, occur the 

 Dimetian and Pebidian rocks, Pre-Cambrian in age, unconformable 

 in position, and discordant in strike ; they constitute the well-defined 

 axis of the St.-David's promontory. 



Menevian* and Lingela-elags. 



In 1865 Messrs. Salter and Hicks gave the name to and established 

 this group of strata in the St.-David's promontory, Pembrokeshire f ; 

 it constitutes the lowest division of the Middle Cambrian of Sedg- 

 wick, and equals his Lower Lingula-flags, and is embraced in the 

 Lingula-flags of authors and the Upper Cambrian of Lyell and Salter ; 

 it is also recognized as being equivalent to Barrande's Etage C in 

 Bohemia ; it occurs in Sweden, has been recognized in North Ame- 

 rica and Canada, and is the St.-John's group in Newfoundland. 



The Menevian is now recognized as a separate division or sub- 

 group, distinguished from the Lingula-flags proper above, as the 

 Ffestiniog of Sedgwick was applied to the Middle and Upper groups 

 of the Lingula-flags in North Wales. In South Wales the Menevian 

 is about 700 feet thick, and more or less fossiliferous throughout. 

 Probably the base of the Menevian cannot be separated from the 

 underlying grits and sandstones of the Harlech and Bangor series, 

 passing as they insensibly do into them, both m North and South 

 Wales, and also into the true Lingula-flags above. No fossils occur 

 or have yet been detected in the grits and sandstones of the imme- 

 diately underlying Harlech rocks, which comprise the structure 

 of the Harlech Dome (Merionethshire anticlinal of Sedgwick) : the 

 same may be said of the great and exposed masses of these Lower 

 Cambrian rocks of the Bangor area, obscure traces of Annelide- 



~* Menasvia is the classic name for St. David's. 



t First announced at the British Association, BirmiDgham, 18(55, ' Eeport/ 

 p. 281. 



