LOWER OLD RED SANDSTONE. Up 



LOWER OLD RED SANDSTONE. 



This division, sometimes known as tlie Cornstone Series, consists 

 of pale and dark grey, yellow and red sandstones, red and variegated 

 marls, shales and mudstone conglomerates, with cornstones in the 

 lower part. Its thickness varies from 1500 to 2500 feet. 



The Rev. W. S. Symonds included the Brownstone Series with 

 the Cornstone Group, but I am informed by Prof. Hughes that 

 it belongs properly to the Upper Old Red Sandstone.^ As before 

 mentioned (p. 118), the Lower Old Red Sandstone has been desig- 

 nated the Sawdde (or Sawddian) Beds by Prof. Hughes. These 

 beds rest on the Upper Ludlow and Passage Beds at Pont-ar-lleche, 

 and in the vale of Gwinfe, and other places. 



The cornstones, as originally described by Buckland, are marl or 

 marlstone, filled with concretions of compact limestone, presenting 

 the fracture and colour of Carboniferous Limestone, varying in 

 size from that of a pea to blocks of many tons, and sometimes 

 spreading out into thick and compact beds, to the almost total 

 exclusion of the marl.- They thus occur in lenticular masses, 

 commonly but a few feet in thickness, and extending from about 

 a hundred yards to two or three miles in length. 



Remains of Crustacea, such as Ptcrygotus (the 'Seraphim' of 

 Scotch quarrymen) and Stylomirus Symofidsii ; also the curious 

 fishes Pteraspis rostratus, Scaphaspis Lloydii, Ccphalaspis Lyellu, 

 Onchiis major-, Zenaspis Salweyi, etc., have been found in the 

 Cornstone Series. The fish-remains in the Cornstones are for 

 the most part fragmentary. Lingida cornea, which is met with 

 in the Downton Sandstones, passes up into beds that have been 

 grouped with the Old Red Sandstone ; its upward limits have, 

 however, not been defined.^ 



The Lower Old Red Sandstone may be studied in the Forest of 

 Hayes, Long Mountain ; in Clun Forest, between Montgomery and 

 Knighton ; and in the neighbourhood of Old Radnor. It extends 

 from near Much Wenlock to Kington, and Brecknock. 



We are informed by the Rev. W. S. Symonds, that " it was at 

 Whitbach, about three miles north-east of Ludlow, that Dr. Lloyd 

 first discovered the shield of a Ganoid fish, which is still in the 

 Ludlow Museum, and bears the name of Scaphaspis Lloydii." 

 Many fossil fishes have been obtained there and at Bouldon, by Mr. 

 Symonds, and Mr. Marston, of Ludlow ; and there, also, have been 

 found the egg-packets of Pterygotus, formerly known under the 

 name of "Parka dt'cipierts." Zenaspis Salzveyi^ was first discovered 



^ Records of the Rocks, p. 212 ; see also J. Phillips, Manual of Geology, 1855, 

 p. 141. 



^ Buckland, T. G. S. v. 512 ; De la Beche, Mem. Geol. Surv. i. 52. 



^ See Godwin-Austen, Q. J. xii. 53. 



^ See Dr. H. Woodward's Monograph of the Brit. Fossil Crustacea, Order 

 Merostomata (Pal. Soc). 



