President's Address. 391 



divided by means of certain special life-zones, characterised 

 by distinct groups of Fishes. 



On the south side of the Grampians he has only definitely 

 recognised one zone, viz., that of " Dura Den." In the Upper 

 Old Eed Sandstone, on the north side of the Grampians and 

 a little on the south side of the Moray Firth, he shows that 

 the Fishes contained in the Nairn Sandstones are different 

 from those of the Elgin Sandstones, and are characterised by 

 Asterolepis maxima, while Bothriolepis major is characteristic 

 of the Elgin beds. Following up a suggestion of Mr Wm. 

 Taylor of Llanbryde, that the fine-grained sandstones of 

 Eosebrae, Elgin, belong to a yet higher horizon than the 

 Alves beds, Dr Traquair shows that they contain fishes 

 allying the fauna to that of Dura Den. 



The exact position of the Old Eed Sandstone of Shetland 

 has hitherto been very uncertain. Dr Flett, however, has 

 lately shown that the rocks of Bressay contain a Fish Fauna 

 which, according to Dr Traquair's determination, indicates 

 that, in part at least, they are of Upper Old Eed Sandstone 

 age, and that they supply a link between the John o' Groats 

 and the Nairn beds. 



Strenuous attempts are at present being made to find out 

 whether the Carboniferous rocks of Scotland are capable of 

 being separated into special life-zones. As regards the marine 

 invertebrate life contained in them, this seems a difficult 

 task; but, as might be expected, the vertebrate life lends 

 itself more readily to that end, and Dr Traquair has clearly 

 proved that, as far as the Fishes are concerned, the formation 

 is sharply divided into two great life-zones, the line of 

 separation lying at the base of the Millstone Grit. 



From the study of the Plants, Mr Kidston comes practi- 

 cally to the same conclusion, the dividing line between the 

 Upper and Lower Carboniferous floras being also at the base 

 of the Millstone Grit. The Lower Carboniferous flora is char- 

 acterised by Lepidodendron veltheimianum. In it Sigillaria 

 and Lepidophloios are present, but are rare, while Astro- 

 catamites is abundant and Catamites extremely rare. Cally- 

 matotheca affinis is a very characteristic fern of the lower rocks 

 of the zone, and that of the Calciferous Sandstones seem to 



