part 2] PALEOZOIC kocks of the llais'gollen district 



The distinctive Asligillian faun; 

 Dolliir Beds is set forth below : — 



187 



The distinctive Ashgillian fauna of this lowest member of the 



Favositesjibj'osusijioldt'uss 



Cf. Monficulipora lens M'Co}' 



Orhicidoidea perrxigata M'Coj' 



Lept(Bna rhomboidalis Wilckens 



Orthis flabellulum J. de C. Sowerby 



Orthis calligramma Dalman 



Orthis calligramma, var. plicata J. de C 



Sowerb}'- 



Orthis (DalmatieJIa) elegantvla Dalmau .. 

 Orthis {Dahnanella) testudinaria Dalman. 

 Orthis (Hebertella) vespertilio J. de C 



Sowerby , 



Plectambonites scissa Siiltev 



Flectambonites sp 



? Triplecia insularis Eichwald 



Agnostus agnostiformis M cCoy 



Agnostus cf. agnostiform is 



Calyviene senaria Conrad (Salter) , 



Calymene cf. caractaci Salter 



Chasmops sp 



Cybele cf. verrucosa Dalman 



lEncrimirtis sp 



Illcemis sip , 



Lichas ?■]) 



Phacops truncato-catidatus Portlock 



Fhillipsinella parabola \^iwvi\w({e 



Sphcerocoryphe thomsoni (?) Eeed 



Triyiucleus cf. nicholsoni Reed 



Trinucleus seticornis Hisinger 



Trinucleus sp 



2. 



(1) Ty'n-y-celyn Farm, near Nantyr. 



(2) Ty'n-y-twmpatli stream, 150 yards north of the farm. 



(3) Lane at Bone. 



(4) Old quarry, by the entrance-lodge to Plas Nantyr. 



(5) Headwaters of Nant-j^-Lladroii, 3 miles south by east of Corwen. 



(h) Upper or Dolhir (sensu stricto) Beds. — The remainder 

 of the Dolhir Beds includes the rocks so desis^nated by Dr. Gi-oom 

 & Mr. Lake near Gljn, and needs no further description so far as 

 the eastern part of their outcrop is concerned. Westwards, how- 

 ever, the group, as mapped by us, thickens (fig. 3, p. 185), and 

 becomes more sand}^ especiallj^ in its upper part, which embraces 

 shalj sandstones that are almost certainly the equivalent of the 

 lower part of the Grlyn G-rit of Gljai-Ceiriog. These beds are not 

 separable in the field from the main part of the group, but their 

 arenaceous nature provides a type of lithologv intermediate 

 between the Dolhir Slates of Grlyn and the greywacke slates and 

 sandstones of the Cyrn-y-Brain Beds. It is accordingly interesting 

 to find Meristina crassa occurring in them as a rarity, for this 

 fossil may be said to be one of the most abundant and charac- 

 teristic forms in the Cyrn-y-Brain Beds. 



The Ashgillian age of the Dolhir Beds was established by 



