﻿Vol. 64.] BA.LA iND LLANDOVEEr EOCKS OF GLTN CEIEIOG. 



577 



in the Bala Series, and draw the line between the Ordovician and 

 the Silurian at the top, not at the base, of the grit. At Corwen, 

 however, there is a much more definite boundary between the Bala 

 Beds and the Corwen Grit, and it is possible that the Glyn Grit 

 and the Corwen Grit do not precisely correspond. 



"^ o 



List op Fossils from tub Glyn Grit 

 AND Limestone. 



Favosites aspera, D'Orb. 

 Halydtes catenularia, Linn. 

 Heliolites megastoma, M'Coy (c). 



Lindstroemia siihduplicata, M'Coy 



Lindstroemia suhduplicata var. crenulata, M'Coy. 



Petraia elongata, Phil, (c) 



Propo7'a tuhulata (?) Lonsd. 

 Streptelasma equisulcatum, M'Coy. 



Glyptocrinus basalts, M'Coy. 



Monticulipor a fibrosa, Goldf. (c) 



Monticulipora lens, M'Coy. 

 Ptiiodictya acuta (?) Hall. 

 Ptilodictya dichotoma, Portl. 

 Ptiiodictya explanata, M'Coy. 

 Eamipora Hochstetteri, Toula var. carinata, R, 

 Eth. (c). 



Athyris (?) sp. 



Glitambonites ascendens. Pander. 



Leptella (?) cf. llandeiloensis, Dav 



Leptcena rhomboidalis, Wilck. (c) 



Lingula ovata, M'Coy 



Meristina (?) cf. nitida, Hall. 

 Meristina (?) cf. angustifrons, M'Coy. 



Orthis ActonicB, Sow 



Orthis biloba (?) Linn 



Orthis calligramma, Dalm. (c) 



Orthis cf. confinis. Salt. 



Orthis crispa (?) M'Coy 



Orthis elegantula, Dalm 



Orthis par va, Pand. (c). 

 Orthis porcata, M'Coy. 



Platystrophia biforata, Schl 



Plectambonites sericea, Sow. (c) 



Plectambonites sp. (c). 

 Bhynchonella cf. Lewisi, Dav. 



Modiolopsis (?) .sp. 



Bellerophon expansus (?) Sow. 

 Holopella temiicincta, M'Coy. 

 Murchisonia (?) cf. pidchra, M'Coy. 

 Pleurotomaria (?) sp. 

 PLatyschisma cf. helicites, Sow. 

 Trochonema triporcatum (?) M'Coy. 



5 to 



Calymene sp. 



Encrinurus 'multiseg merit at us 



Pkacops Robertsi, Keed. 



Portl. 



