468 British Association — J. Home, F.R.S., etc. — 



stratigraphical horizons Dicynodonts and Labyrinthodonts being found 

 in the lower Panchetp ocks, while Hyperodapedon and Parasuchus (allied 

 to Stagonolepis) are met with in the higher Kota-Maleri beds. Again, in 

 the Karoo beds of South Africa the Dicynodonts and the great Pareia- 

 saurus — the latter being the nearest known ally of the horned reptile 

 {Elginia mirabilis) from Cutties Hillock, Elgin — occur low down in that 

 formation. Further light is thrown on the question by the interesting 

 discoveries of Amalitzky in Northern Russia, where a number of reptilian 

 remains have been found closely allied to Pareiasaurus, Elginia, and 

 Dioynodon, in beds which are referred to the Permian formation, and 

 accompanied by plants and moUusca which seemingly confirm this 

 reference. ^ 



In view of these foreign discoveries Mr. Newton concludes that the 

 Elgin sandstones may probably represent more than one reptilian 

 horizon, and that we are confronted with the possibility of their being 

 of Permian age. 



The difficulty of drawing a boundary-line between the Trias and the 

 Upper Old Red Sandstone of Elgin, which impressed the mind of the late 

 Dr. Gordon, has had to be faced elsewhere in Scotland. In Arran, my 

 colleague Mr. Gunn has shown that the Trias there rests on the Upper Old 

 Red Sandstone, both formations having a similar inclination. Even he, 

 with his ripe experience, has had great difiiculty in drawing a boundary 

 between them on the west side of the island ; but when the base-line of 

 the Trias is traced eastwards to Brodick it passes transgressively on to 

 Carboniferous rocks. 



Of special importance is the recent discovery in Arran of the fossils of 

 the Avicida contorta zone - by Mr. Macconochie, of the Geological Survey, 

 to whose skill as a fossil collector Scottish geology owes much. With 

 these occur Lower Liassic fossils, in sediments which are not now found 

 in place in the island. These fossiliferous patches are associated with 

 fragmental volcanic materials filling a great vent, the age of which will be 

 referred to presently. This discovery has fixed the Triassic age of the 

 red sandstones and marls in the south of Arran. The detailed mapping 

 of the island by Mr. Gunn has demonstrated that the Triassic sandstones 

 rest partly on the Old Red Sandstone, partly on the Carboniferous Lime- 

 stone Series, and partly on the Coal-measures. 



In 1878 appeared the third of Professor Judd's great papers on the 

 Secondary Rocks of Scotland, wherein he unravelled the history of these 

 strata as developed in the east of Scotland and in the West Highlands. 

 His admirable researches, in continuation of the work done by Bryce, 

 Tate, and others, embraced the identification of the life -zones, their 

 correlation with those of other regions, the history of the physical con- 

 ditions which prevailed in Scotland during Mesozoic time, and the working 

 out of the structural relations of the strata.^ He showed that their 

 preservation on the east of Scotland was due to the existence of great 

 faults, and those in the West Highlands to the copious outpouring of the 

 Tertiary lavas. He was the first to detect the occurrence of Cretaceous 

 rocks in the West Highlands, and to show the marked unconformability 

 which separates them from the Jurassic strata. His main life-zones and 

 his main conclusions regarding the Secondary Rocks of Scotland have so 

 far been confirmed by the detailed mapping of the Geological Survey. An 

 interesting addition to our knowledge of these rocks was made by my 

 colleague Mr. Horace B. Woodward, in the course of his field-work, who 



1 T. Amalitzky: " Sur les fouilles de 1899 de debris de vertebres dans les depots 

 Permiens de la Russie du nord," Varsovie, 1900. 



2 Summary of Progress Geol. Surv. 1899, p. 133. 



2 Quart. Joum. Geol. Soc, vol. xxix, p. 97 ; vol. xxxiv, p. 660. 



