TRANSACTIONS OF SECTION C. 627 



that system. It further appears that Osteolepidee (Osteolepis, Dt'plopterus), 

 ■ RhizodontidcB {Tristichofferus, Gj/voptychius), Holopti/chiidce {Glytolepis), 

 Asterolepidee (Pten'chth/s, Microhvachius), Ctenodontidce (jDipterus) are abundant 

 in the Orcadian fauna, none of which has occurred in the Lower Old Red Sand- 

 stone of Forfarshire, the West of England, or in the Lower Devonian rocks of 

 Canada. Dr. Traquair recognised, however, the identity of the fishes from the 

 well-known fish band in the basin of the Moray Firth with those brought from the 

 west part of Orkney, though these forms did not quite agree with the fossils from 

 the Thurso district. He subsequently found that the fish fauna from the Orcadian 

 beds in the Moray Firth basin is represented in Caithness by that of Achanarras ; 

 and, further, that two other faunas occur in the Caithness area — that of Thurso 

 and that of John o' Groats as given below : — 



John o- Groats . . . | 2';'/««f'''i'^«'-w-'«?«^««, Egert. 



r Cooco.ifeus minor, H. Miller. 



Thurso - Thvrsius 2^fiolidotus, Traq. 



I Osteolejns microlepidotus, Pander. 



r Pterichthys, 3 species. 



Achanarras . . . . ■' Cheirolepis Traill!, Ag. 



[. Osteolepis macrolepidotus, Ag. 



Li 1898 appeared an important paper by Dr. Flett on ' The Old Red Sandstone 

 of the Orkneys,' ' in which he described the results of his detailed examination of 

 the islands. He proved the existence there of three fish faunas, and their 

 correspondence with those identified in Caithness by Dr. Traquair. From the 

 evidence in the field he adopted the following order of succession and correlation 

 of the strata : — 



3. Eday Sandstones and John o' Groats beds. 



2. Rousay and Thurso beds, 



1 . Stromness, Achanarras, and Cromarty beds. 



A further important result of Dr. Flett's researches in the Old Red Sandstone 

 of these northern isles was communicated to the Royal Society of Edinburo-h this 

 year. He has found in the Shetland beds, which had previously yielded no' fossils 

 save plants, fragments, identified by Dr. Traquair as Holonema, a fish new to 

 Bi-itain, but occurring in the Chemung group of North America, the subdivision 

 of the Upper Devonian that immediately underlies the Catskill red sandstones 

 with remains of Holojitychius. Dr. Traquair has also recognised in Dr. Flett's 

 collection fragments of Asterolepis, a genus characteristic of the Upper Old Red 

 Sandstone, and which, as proved by Dr. Flett, occurs in the ' Thurso beds ' of the 

 Orkneys. The interest attaching to this discovery is very great, for Dr. Flett 

 contends that it indicates a fourth life-zone in the Orcadian series, and, further 

 that it tends to span the break between the Orcadian division and Upper Old Red 

 Sandstone. 



In the Upper Old Red Sandstone on the south side of tbe Moray Firth, Dr. 

 Traquair recognised two life-zones, and subsequently, with the assistance of 

 Mr. Taylor, Lhanbryde, a third ; in the following order. The lowest is that of the 

 Nairn sandstones with Asterolepis maxima (Ag.) ; the second, that of Alves and 

 Scaat Craig with Bothriolepis major (Ag.), Psammosteus Taylori (Traq.) ; and the 

 highest that of Rosebrae, the fauna of wbich, according to Dr. Traquair, has a 

 striking resemblance to the assemblage in the Dura Den Sandstones in Fife'. 



Before 1876 all the Carboniferous areas in the great midland valley of Scotland 

 had been mapped by the Geological Survey. The extent and structural relations 

 of the various coal-fields were determined according to the information then 

 available, and shown in the published maps. But the rapid development of certain 

 fields in the east of Scotland necessitated a revision of them which has lately been 

 done. The Fife coal-field has been re-examined by Sir A. Geikie, IMr. Peach and 



' Trans, Roy. Soc. Edin., vol. xxxix. p. 383. 



