338 STKATIGRAPHICAL GEOLOGY 



near Ardtrea in Tyrone, at both of which they include fossiliferous 

 magnesian limestones ; at the third place (Armagh) there are only 

 boulder-beds and breccia resting on Carboniferous limestone. 



5. Scotland 



In Dumfries and Ayrshire there are tracts of bright-red sand- 

 stone which have much resemblance to the Penrith sandstone, but 

 till recently no evidence for their identity was forthcoming, and 

 consequently they were regarded by some as belonging to the 

 Trias, and were so classed in the last edition of this book. Mr. 

 G. Hickling, 8 however, has compared the Eeptilian footprints of 

 the Dumfries sandstones with those of the Penrith Beds, and finds 

 that though not identical they are similar, and differ from those on 

 Triassic sandstones, and further that two of the types seem to be 

 identical with prints in the Permian sandstone of Mansfield 

 (Nottingham). 



Dumfries. In this district the three largest tracts are (1) one 

 extending from the Solway Firth by the mouth of the Nith to and 

 beyond the town of Dumfries, (2) round Lochmaben in Annandale, 

 and (3) round Thornhill in Nithsdale. Professor Harkness was 

 of opinion that the general succession of the beds near Dumfries 

 and Lochmaben is as follows : 



Feet. 



4. Thin-bedded sandstones with beds of clay . . . 300 

 3. Hard massive breccias and conglomerate . . . 300 

 2. Soft red current-bedded sandstones \ - ~ 



1. Coarse sandstones and breccias J 



The breccias consist of angular blocks and fragments of various 

 Palaeozoic rocks, with some of granite and other igneous rocks, 

 embedded in red sand. The lower sandstones are brick-red in- 

 colour, frequently flaggy and divided by thin seams of dark-red 

 clay, and their surfaces often bear the footprints of Labyrinthodont 

 and other reptiles. Such footprints were first described by 

 Professor Buckland from specimens found in the quarries on 

 Corncockle Moor near Lochmaben, but they are equally common 

 near Dumfries ; they also occur in the upper sandstones, the beds 

 of which are separated by rather thicker layers of clay. 



In the Thornhill basin farther north there are no breccias, and 

 the greater part of the tract consists of brick -red sandstone, but in 

 the northern part lava-flows and volcanic detritus are interstratified 

 with the lowermost sandstones. The higher sandstones contain 

 beds of shale and clay, and seem comparable to the higher beds 

 near Dumfries. 



