[To face pay e 42. 



Table of the Strata, and the Order of Appearance op Life, in the Cambrian Rooks of Great Britain. 



Lithological Characters. 



Thickness of 

 Strata. 



Order of the appearance of Life. 



Genera. 



Classes, Orders, 



Typical Localities. 





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f 



Upper Tremadoc 

 Middle Tremadoc 



Lower Tremadoc 



<T-( Upper Lingula-uags 

 (Dolgelly Group, 

 Belt). 



Middle Lingula-flags f 

 (F/'estiniog Group, \ 



Lower Lingula-flags 

 Maentwrog Group, 

 Belt). 



Menevian Group 



Longmynd, or Har- 

 lech Group. 



Iron-stained slates and flags , 

 Dark earthy slates 



Grey flaggy sandstones 



Soft black and bluish slates in 

 North Wales ; bluish and 

 grey flags in South Wales. 



Grey arenaceous and 

 slates and flags. 



Bluish slates and flags, and 

 alternating bands of yellow- 

 ish grey shales and sand- 

 stones. 



Thick beds of sandstone with 

 shale. Dark blue slates and 

 flags, dark grey flags, and 

 grey gritty beds. 



Grey, purple, and red flaggy 

 sandstones ; yellowish-grey 

 sandstones, shales, and flags; 

 purple sandstones, some- 

 times with greenish bands ; 

 red, flaggy, or shaly beds ; 

 greenish flaggy sandstones, 

 conglomerates, and greenish 

 ironstones. 



tru 



South Wales. 

 Supposed to 

 be over 8000 

 in N. Wales. 



Angelinia, Conularia, Lingulo- 



Cheirurus, Asaphus, Dictyo- 

 nema. 



Dendrocrinus, Palasterina, Or- 

 thoceras, Glyptarca, Davidia, 

 Modiolopsis, Niobe, Cteno- 

 donta, Palfearca. 



Eophyton, Neseuretus, Sphrer- 

 ophthalmus, Dikelocephalus ?, 

 Parobolina, Peltura. 



Bellerophon, Hymenocaris, 

 Buthotrephes. 



Olenus and a phyllopod crusta- 

 cean. 



Stenotheca, Orthis, Protocysti- 



tes, Cyrtotheca. 

 Carausia, Entoinis, Erinnys, 



Holocephalina, An opolenus, 



Arionellus. 



Hydrozoa. 



Crinoidea, Asteroidea, 



Cephalopoda. 

 La nielli branchi ata. 



Laud Plants (?) 



Heteropoda. 



Phyllopoda. 



Theca. 



Obolella. 



Conocoryphe. 



Paradoxides. 



Plutonia. 



Microdiscus. 



Pteropoda 



Haughtonia. 



Histioderma. 



Scolithus. 



Arenicolites. 



Oldhamia. 



Agnostus*. ' Trilobita. 

 Protospongia*. Spongida. 

 Leperditia (?). Entomostraca (?). 

 Discina. |Plantse (?). Brachiopodi 



Lingulella. Polyzoa (?). Annelida. 



Portmadoc and Dolgelly, in 

 North Wales. 



Tremanhire, Ramsey Island, 

 and Llanveran, near St. Da- 

 vid's, in South Wales. 



Malvern, Dolgelly, and near 

 Portmadoc. 



Maentwrog, Dolgelly, and at 

 Ramsey Island, near St. 

 David's. 



Neighbourhood of Maentwrog, 

 Dolgelly, and St. David's. 



St.David's.in SouthWales ; and 

 neighbourhood of Maentw- 

 rog, and Dolgelly, in North 

 Wales. 



St. David's, in South Wales; 

 Harlech, Bangor, &e., in 

 North Wales ; Longmynd, 

 in Shropshire ; and Bray 

 Head, in Leland. 



Found recently at the base of the Cambrian Bocks of St. David's. 



