(To face p. 20.) 



Table I. — Fossils op the Older Paleozoic (Protozoic) Rocks in North Wales. Drawn up by Messes. J. W. Salter and J. de Carle Sowerby. 



Note.— Columns I. 2. and 3. are added to this List on the authority of Professor Sedgwick's paper , other Fossils belonging to those Columns are to he found in Column 4. [Ed.] 



NAMES OF GENERA 



Localities taken in the Ascending Order. See Section I. 



Slates ' Dark earthy 



West I Slates 



of I E. of 



Arenig Arenig 



Crustacea. 

 Agnostus pisiformis - 

 Illsnus Bowinani (n.s.) 

 paradoxides (n. s. ?) 

 Tiinucleus Caractaci - 

 fimbriatus - 

 Asaphus Buchii 

 tyrannus 

 Powisii 

 caudatus 

 (n.s.) 

 Calymene Blumenbaohii 

 (n s.) - 



n. s. ? with granulated head 

 Entomostracites punctatus 



itollusca. — 'Cephalopoda. 



Nautilus primarvus 



Lituites cornu arietis - 



Phragmoceras? (n. s. ?) 



Orthoceras, smooth and distant septa 

 smooth and close septa 

 smooth and conical 



Heteropoda. 

 Bellerophon bilobatus 

 nodosus - 



Pteropoda. 

 Conularia quadrisulcata 



Gasteropoda. 

 Pleurotomaria (n.s. angular) 

 Murchisonia (de Vern.) 



(n. s. ? large) 

 Turbo Prycea? 

 Littorina striatella 

 Euomphalus funatus - 



(n.s.) - 



Conchifera. 

 Area Eastnori ? 

 Nucula ? (n. s. ) 

 Cypricardia (n. s. ) 



(n.s.) - 



(n.s.) - 



Brachiopoda. 

 Lingula (n. s. ?) - 



Terebratula decemplicata 



tripartita 



crispata - 



marginalis* (imbricata) . 



(n.s.) - 



(n.s.) - 



(n.s.) - 

 Atrypa affinis 



Giay Ilhiwlas 



Slates and Moel- 



E. of i y-Gamedd, 

 Arenig W. of 



Fawr. Ikil.i l.nl. ... 



Ihiuii.id 



Gh'n- 



IhllVus. 



Col. 8. Hee Sec. I. 



to Pennant 

 Manwddvn. 



+ + 

 + + 



In the Ascending Order. See Sec. IV. 



+ + + 

 + + + 



Pont- j - 



Meiliion lo 



.'. L I. I.I -u 



drillo. 



+ + 



+ + 



Calcareous Shale. 



Or the foregi 

 the folloi 



nd alsoii 



Silurian rocks 



following 



found also in the Upper 



t: 'urian rocks of 



N. Wales. 



Wenlock Lime- 

 I stone. 



The names marked with an asterisk are names substituted for those given in the Silurian system, in consequence of the examination of a collection from Sweden, in the possession of Mr. Murchison. 



