60 Geological Society. 



December 7, 1887.— Prof. J. W. Judd, F.E.S., 

 President, in the Chair. 



The following communications wore read : — 



1. " On the Discovery of Trilobites in the Upper Green (Cam- 

 brian) Slates of the Penrhyn Qnarry, Bethesda, near Pangor, North 

 Wales." By Dr. Henry Woodward, P.K.S., V.P.G.S. 



The absence in Wales of organisms in the Longmynd and Harlech 

 group renders any discovery of fossils in beds of this early horizon 

 of the utmost importance. 



A portion of a Trilobite {Palo'ojyyge Bamsayi) and Annelide bur- 

 rows had already been found; but Dr. Hicks, at St. Davids, has added 

 a sponge, 2 Ostracods, G Trilobites, 2 LiiH/uUlIa', and 2 Thecce 

 (Af/iiostus, Plutonia, Paradoxides, Conocoryplie Lyelli, C. hufo, and 

 3Iici'odiscus sculpt us). 



Dr. Hicks has pointed out the singular absence of organic remains 

 in the Longmyuds in Shropshire, N. Wales, and Ireland, and 

 has urged the need of further explorations. As if in answer to this, 

 the Author has received from Prof. Dobbie an impression and counter- 

 part of a Trilobite from Bethesda, near Bangor, about Sg in. long and 

 1| in. broad, also the head of a second specimen of the same species. 

 These specimens were obtained from the Upper Green bed of the 

 quarry, which immediately underlies the grits forming the brow of 

 Eronllwyd and above the Purple Slates. The glabella is marked by 

 three oblique furrows on each side, the cheek-sutixres are very 

 obscure, and the eyes, which are minute (probably rudimentary), 

 occupy the centre of the free cheek, the suture obliquely dividing the 

 free cheek from the fixed. The outline of the head is rounded. 

 There are fourteen free thoracic segments. The pygidium consists 

 of about three coalesced somites. 



Comparing the Bangor fossil with Paradoxides, we find that 

 Paradoxides has about twenty free segments. 



Asaphus, Oijygia, and Niol>e have only eight thoracic rings, and 

 the caudal shield is very large. 



Angelina agrees with the Bethesda specimen in the number of 

 its free segments ; but the glabella is smooth, the pleuroe are broader, 

 and the cheek-spines very long. 



Olenus has fourteen rings ; the glabella is furrowed, but the head- 

 shield ii^ shorter and broader, and the ends of the pleurte and margin 

 of the caudal shield are usually produced into spines. Olenus is also 

 smaller. 



ConocorypiJie has fourteen free segments ; the axis is parallel- 

 sided, and does not diminish backwards from the head to the 

 pygidium ; each ring of the axis is notched on its posterior border, 

 and the ends of the pleurae are rounded ; the glabella is furrowed 

 obliquely ; the eyes are often wanting or are minute. 



From these considerations the Author considered the Bangor fossil 

 to be referable to Conocoryplie, and to a new species. 6'. viola. 



