238 Proceedings of the Royal Physical Society. 
the Southern Uplands and the Cheviots, the old valleys filled up with coarse 
conglomerates which are of the nature of torrential deposits. Owing, doubt- 
less, to a general subsidence of the area, these deposits and the enclosing 
hills are overlaid by Red Sandstones and marls alternating with conglomerates, 
indicating that they were laid down either in enclosed water basins subject 
to periodic desiccation, or upon land surfaces where torrents debouched upon 
the plains leaving their deposits to be partly assorted by wind during dry 
intervals. At several horizons, but more particularly near the top of the 
pile of sediments, the marly beds contain nodules and sometimes considerable 
beds of cornstone, a concretionary limestone evidently formed, like Kunka 
of India, within the sediments after deposition and at the upper mit of 
saturation, the lime being largely derived from contemporary volcanic rocks. 
Accompanying this subsidence of the area, and probably in some way 
directly connected with it, vulcanicity manifested itself; and volcanoes broke 
out in at least three separate areas. The most extensive volcanic platform 
they gave rise to, is that which extends from the Berwickshire Merse to 
beyond Birrenswark in Dumfriesshire. A second is situated in the Kilsyth 
part of the Campsie Plateau, while the third occurs sporadically scattered 
through the Orkney and Shetland Islands. 
The mode of occurrence of the fossil fishes, which are generally found 
crowded together and almost whole, sometimes enclosed within an inch or so 
of strata, while the intervening large masses of sediment only yield an 
occasional detached scale or tooth, had long suggested to geologists that the 
fishes had been entombed in shoals in dried-up pools. This conjecture has 
recently been confirmed during the excavations at Dura Den, carried out by 
the British Association Committee appointed at the Dundee meeting in 1912, 
The bed containing the crowded fish remains, belonging to several genera, was 
found to be sun-cracked. Further, the presence of Phaneroplewron, one of 
the Dipnoi or lung-fishes, and the nearly allied genus Holoptychius, in the 
assemblage of fishes got there, is strong evidence in favour of land-locked and 
not marine conditions of deposit. 
Evidence of desiccation during the deposit of the Upper Old Red Sand- 
stone near Edinburgh is admirably shown in the Suburban railway cutting 
at Craiglockhart, where the marls and more clayey bands are widely and 
deeply fissured by sun-cracks that are filled in by sandstone continuous with 
the overlying sandstone layers. 
ONCOMING OF THE CARBONIFEROUS PERIOD IN SCOTLAND. 
The continued depression which converted the Upper Old Red land 
surface into the Carboniferous sea was widespread and more pronounced in 
