1866.] 



PLANT PRIMORDIAL FOSSILS. 



505 



Edinburgh. The wedge-shaped rostral portion is absent from this, 

 specimen. 



The same, in which the shield is folded together. Natural size. Col- 

 lection of Mr. D. J. Brown, Edinburgh. 



Peltocaris aptychoides, Salter. Moffat Shales, Dumfriesshire. Three 

 times the natural size. Collection of W. Carruthers, Esq., F.L.S. 



Discinocaris Browniana, having the wedge-shaped rostral portion in situ. 

 Natural size. Collection of W. Carruthers, Esq., P .L.S., of the British 

 Museum. 



5. Notes relating to the Discoyery of Primordial Fossils in the 

 LiNGULA-ELAGS in the Neighbourhood of Tyddyngwladis Silyee- 

 LEAD Mine. By John Plant, Esq., P.G.S. 



[Abstract.] 

 The author recorded in this paper the discovery, during the autumn 

 of 1865, of fossils at Tyddyngwladis in beds belonging to the Lin- 

 gula-flags or Primordial zone, and partly referable to species known 

 to occur in other parts of Wales on the same horizon. 



A detailed examination of the district, undertaken by the author 

 and Mr. E. Williamson, has enabled them to draw a section ex- 

 tending from the junction of the Lower and Upper Cambrians* at 

 Cefn Deuddwr to the base of Craig-y-Dinas, which was described 

 in detail t by the author. 



The following list of the fossils found in the various divisions of 

 the Lingula-beds adopted by the author, and arranged in their order 

 of sequence, commencing with the lowest, have been prepared, after 

 Mr. Salter's examination of the collection. 



Tyddyngivladis Slates (Loiver Lingula-beds). 



No. 1. Has not been examined. 

 No. 2. Anopolenus Henrici, Salter. 



Salteri, Hides. 



, sp. 



Paradoxides Hicksii, Salter. 



Microdiscus punctatus, Salter. 



Agnostus Davidis, Salter. 



princeps, Salter. 



, sp. 



Theca, sp. 



No. 2. Lingulella unguiculus, Salter. 



, sp. 



Obolella, sp. 



Protospongia fenestrata, Salter. 

 |Dictyonema G-raptolithinum ? 

 No. 3. Agnostus, sp. 



Obolella, larger sp. 

 No. 4. Paradoxides Davidis, Salter. 



Theca corrugata, Salter. 



Cwm Eisen Slates {Lower Lingula-heds). 



No. 5. Olenus cataractes, Salter. 



, sp. nov. 



Agnostus princeps, Salter. 



No. 5. Agnostus trisectus, Salter. 

 Tract of a Trilobite. 

 Holocephalina, sp. 



Hafod Owen Sandstones (Middle Lingula-heds). 



No. 



Olenus, sp. nov. 

 Conocoryphe, sp. nov. 

 Lingulella Davisii, Salter, 



No. 6. Hymenocaris? 



Annelid-tracks and borings. 

 JButhotrephis (fucus). 



* The Upper Cambrians of this author comprise the Lingula-flags, or base 

 of the Lower Silurian, of Sir Eoderick Murchison and other geologists. 



t Published in fall in the Transactions of the Manchester Ceol. Soc. vol. v. 

 p. 220 et seq. 



1 These are not Mr. Salter's naming, 



2m2 



