W. J. SOLLAS ON THE SILURIAN OF CARDIFF. A475 
37. On the Sttvrian District of Raymnry and PENn-Y-LAN, CaRpIFr. 
By W. J. Sours, Esq., M.A., F.G.S., Lecturer on Geology, Uni- 
versity College, Bristol, and Curator of the Bristol Museum. 
(Read April 9, 1879.) 
[Puare XXIV.] 
Tne occurrence of rocks containing typical Silurian fossils at several 
places near Cardiff, and over an area mapped as Old Red Sandstone 
by the Geological Survey, was first brought to my notice by my 
friends Captain J. Carne Ross, F.G.S., and Mr. W. H. Harris, of 
Cardiff. This was in the autumn of 1875; and as I was then 
commencing a stay of six months at Cardiff, I was able to accompany 
my friends to the sections they had discovered, and to confirm their 
observations. 
Mr. Ross and myself then devoted ourselves to a careful study of 
the neighbourhood, with the intention of writing a joint paper on 
the subject ; but when we had made a considerable advance in our 
work, Mr. Ross removed to a distant part of the country, and I was 
left (much to my regret) to complete the paper without his aid. My 
friends Messrs. R. Jones and T. Jones, F.G.S., both of Newport, and 
Messrs. W. H. Harris and J. Storrie, of Cardiff, came, however, to 
my assistance ; and to them I am indebted for many valuable sug- 
gestions and for the clearing-up of many doubtful and difficult 
points. ; 
Mstory. 
The whole of the district I am about to describe is coloured as 
Old Red Sandstone on the maps of the Geological Survey ; but that 
Silurian rocks exist at Pen-y-lan hill and in its neighbourhood was 
made known so long ago as 1861 by Norman Glass*, who collected 
a number of fossils from the Pen-y-lan quarry, and sent them for 
determination to Sir Roderick Murchison and Mr. Salter. A list of 
these fossils was drawn up by Mr. Salter, and the beds were assigned 
to the Wenlock series. Mr. Bevan, F.G.S., next examined the 
district, and published a paper upon it, to which, however, I have 
not succeeded in obtaining a reference. Mr. Etheridge tells me that 
Mr. Aveling also has paid a visit to Pen-y-lan; but no record of his 
observations appears to have been published. I am not aware that 
any other literature exists on the subject. 
Geographical Distribution. 
The alluvial plain on which Cardiff is situated extends northwards 
to the edge of the old Paleozoic tableland of South Wales, and 
meets it along a line extending from Llandaff railway-station on 
the west to Rhymney bridge on the east. From this line to the 
southern escarpment of the limestone of the Coal-basin the table- 
land rises gently to the north, and is cut up by three transverse 
* «The Geologist,’ 1861, p. 168. 
