74 



DR. H. WOODWARD ON THE DISCOVERY OF TRILOBTTES 



8. On the Discoyery of Trilobites in the Upper Green (Cambrian) 

 Slates of the Penrhyn Qfarries, Bethesda, near Bangor, 

 North Wales. By Henry Woodward, LL.D., F.E.S., Y.P.G.S. 



(Read December 7, 1887.) 



[Plate IV.] 



The Cambrian rocks of Wales, once so barren of all evidence of 

 organic remains, have now, thanks to the late Mr. J. W. Salter and 

 Mr. T. Belt, to Mr. Homfray of Portmadoc, but most of all to the 

 researches of Dr. Henry Hicks, P.R.S., at St. Davids and elsewhere, 

 become peopled with an extensive series of organisms, amongst 

 which the Trilobites make up a large proportion of the fauna *. 



It is true that the Longmynd Group elsewhere had only yielded 

 Annelide-burrows and a portion of a Trilobite (Palceojoyge Ramsayi) ; 

 but the investigations of Dr. Hicks at St, Davids have contributed 

 a Sponge (Protospongia major'), two Ostracods (Leperditia cambrensis 

 and L. Hicksii), eight Trilobites (Agnostus cambrensis, Phitonia Sedg- 

 wickii, Paradoxides Harlcnessi, P. aurora, P. HicJcsii, Conocoryphe 

 Lyelli, C. hufo, Microdiscus sculptus) : in addition to which two Lin- 

 gulellce and two Thecce must be added. 



The following table shows the fauna of each formation, from the 

 Longmynd up to the Tremadoc : — 











Crustacea. 









.1 









Cambrian. 





1 

 1 



S 



1 



4 

 1 





i 

 1 



^ 



e3 



1 



1 



p-i 



1 



03 



I 



4 



3 





&I 



S 



o 



m 



^ 



"S 



o 



a 



ti 





43 



c 



o 





oq' 



w 



o 



2 



36 



1 



-^ 



12 



12 



15 



2 



H 

 85 



5. Tremadoc Slates . 





2 



3 



4. U. Lingula Flags 



... 











25 



1 



3 



6 









35 



3. L. Lingula Flags 









1 



1 



8 



... 



4 



2 





3 



... 



19 



2. Menevian 



8 





1 







9r, 







8 





5 





87 



1. Longmynd Group 



1 







2 





7 





3 



2 



... 



2 



... 



17 



Dr. Hicks writes : — " The Longmynd series, so well exposed in 

 coast-sections at St. David's, is evidently identical with that of North 

 Wales and Shropshire, the Hthological characters and the order of 



* No fewer than 25 genera and 85 species of Trilobites are recorded from the 

 Longmynds to the Tremadoc Slates. 



