DESCRIPTION OP THE FORMATIONS 379 



THE UPPER OLD RED SANDSTONES 



Of these rocks in Scotland and England, A. Geikie makes the following 

 statements : 



"This division consists of red sandstones, deep-red clays or marls, conglom- 

 erates, and breccias, the sandstones passing into yellow or even white. These 

 strata, wherever their stratigraphical relations can be distinctly traced, lie 

 unconformably upon every formation older than themselves, including the 

 Lower Old Red Sandstone, while, on the other hand, they pass up conformably 

 into the Carboniferous rocks above. As already remarked, they were deposited 

 in basins, which only partially correspond with those wherein the Lower Old 

 Red Sandstone had been laid down. Studied from the side of the underlying 

 formations, they seem naturally to form part of the Old Red Sandstone, since 

 they agree with it in general lithological character, and also in containing 

 some distinctively Old Red Sandstone genera of fishes, such as Bothriolepis, 

 Goccosteus, and Holoptychius; though, approached from the upper or Carbon- 

 iferous direction, they might rather be assumed as the natural sandy base of 

 that system into which they insensibly graduate. On the whole, they are re- 

 markably barren of organic remains, though in some localities (Dura Den in 

 Fife, Lauderdale) they have yielded a number of genera and species of fishes, 

 crowded profusely through the sandstone, as if the individuals had been sud- 

 denly killed and rapidly covered over with sediment. Among the distinctive 

 fossils of the Upper Old Red Sandstone are species of Asterolepis, Bothriolepis 

 (formerly confused with Pterichthys) , Goccosteus, Gonchodus, Gosmacanthus, 

 Glyptopomus, Gyroptychius, Holoptychius (four or more species) , Phanero- 

 pleuron, Phyllolepis, Polyplocodus and Psammosteus. . . . 



"In the north of England sandstones and conglomerates representing the 

 ordinary type of the Upper Old Red Sandstone emerge from underneath the 

 Carboniferous formations, and lie unconformably on Silurian rocks and Lower 

 Old Red Sandstone. Some of the brecciated conglomerates have much resem- 

 blance to glacial detritus, and it was suggested by Ramsay that they have 

 been connected with contemporaneous ice-action. ... In South Wales and 

 the border counties of England, as already stated, the Carboniferous series 

 passes down conformably into the Upper Old Red Sandstone, which cannot at 

 present be separated from older parts of the system." S4 



Describing in more detail the Upper Old Red Sandstones of Kinross, 

 A. Geikie states : 



"Well-bedded red, grey, purple, and white sandstones, with thin partings of 

 red shale or marl, may be seen for nearly two miles up the Glen Burn. These 

 strata are often flaggy or false-bedded, and many of them are crowded with 

 'galls' or flat pellets of red or purple clay. Some of the beds of this character 

 contain plentiful fragments of Holoptychius, which may be readily detected 

 by their white or yellowish colOr on the dark ground of the stone. A good 

 locality for searching for ichthyolites will be found at the upper end of the 

 Gospetry fir-wood, above the road that passes by Moors of Kinnesswood and 

 Lappiemoss. A thin band of yellowish sandstone, well charged with clay-galls 

 and containing fragmentary fish-remains, crops out at the foot of the scar on 



34 Text-book of geology, 1903, pp. 101 0-1012, 



