MALCOLMSON" OLD EED SANDSTOIfE. 



337 



son ; the reader is therefore referred to the two next following Memoirs for the 

 plan and details of the classification at present adopted. — Ed. Q. J. Gr. S.] 



Contents. 



Introduction. 



Inferior or Grreat Conglomerate. 



Fossiliferous strata of the Central Di- 

 vision of the Old Eed Sandstone. 



Section on the Findhorn. 



Fossils of the Central Division. 



Sections through the Middle and Lower 

 Sandstones on the Burn of Lethen. 



Fossils in the Valley of the Nairn. 



Fish-beds of the Spey, and of Tynat 

 and Buckie in Banffshire. 



Sections at Tynat and Buckie. 



Conclusion ; with Eemarks on Cro- 

 marty and Gamrie. 



Appendix : Old Eed Sandstone of the 

 Orkney Islands. 



Introduction. — The object* of the following paper is to show that 

 the vast series of rocks in the North of Scotland included under the 

 name of the Old Red Sandstone system f may be separated into several 

 great subdivisions, two of which are characterized by numerous 

 organic remains of very peculiar and distinct forms ; and to identify 

 with these subformations, as exhibited along the southern shores of 

 the Moray Frith, the vast fossiliferous strata belonging to the same 

 system in Caithness and the Orkneys, and in the South of Scotland 

 and in England. The following tabular statement embraces a general 

 view of these divisions as exhibited in the counties of Moray and 

 Nairn, and in the adjoining parts of Banff and Inverness, in the 

 ascending series, which I have adopted on the present occasion to 

 avoid the confusion that might arise from commencing the enume- 

 ration from the broken and denuded portions of the comparatively 

 ill-ascertained strata forming the highest rocks of the series. 



A. Elevated and contorted gneiss traversed by granite- and por- 

 phyry-dykes. 



B. Old Eed Sandstone. 



1st or Lower division : subdivided into — 

 a. " The Great Conglomerate ;" consist- 



ing of vast beds of a very coarse con 

 glomerate with bands of red sandstone. , 



b. !Red Sandstones, shales with calca- 

 reous nodules, and hmestones, abound- 

 ing in remains of fishes and plants. 



a. W. coast of Scotland and 

 southern side of the Gram- 

 pians. 



h. Orkney and Caithness ; bitu- 

 minous flagstones with fishes 

 and plants, galena, blende, and 

 copper. 

 TUe-stones of England. 

 Argillo-calcareous Sandstones and 1 c. White and yellow Sandstones 

 Conglomerates, mostly of a deep -red I of Orkney and Caithness, and 

 colour, sometimes black or white. J of Cromarty and Easter Boss. 



2. Central division or Cornstone series. "^ 



Sandstones, caleiferous conglomerates, I ^^i , , • • • tj i-i, ^,• 

 ^ « ' , -, . . ° . p Clashbmnie m Perthshire, 

 maris, &c., aboundme; m remams oiv-rr ^jr,- n *- 

 ax. XI ;\-w A-x- i.\. xf-\r i i. \ Hereiordshire Comstones. 

 fishes, ail dilierent irom those oi JN o. 1 , 6. | 



Contains beds of Cornstone J. J 



* [This introduction was added by the author subsequently, it appears, to the 

 reading of the Memoir. — Ed. Q. J. G. S.] 



t I here adopt the term " system" as first appUed by Mr. Murchison to the 

 Old Red Sandstone ('Silurian System,' p. 169). 



I The upper beds at Nairn consist of a sOiceous conglomerate with remains of 

 fish. Some of the beds of this rock furnish one of the finest building-stones in 

 Scotland. 



2c2 



