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XIII.— The Old Red Sandstone of the Orkneys. By John S. Flett, M.B., B.Sc. 



. (With a Map.) 



(Bead 17th January 1898.) 



Literature. 



The first geologist to examine critically the Old Red Sandstone of the Orkneys seems 

 to have been Professor Jameson, who in 1800 spent six weeks in a mineralogical tour 

 through the county, and so barren did he find the islands, from his point of view, that 

 he counted his journey one of the most uninteresting he had ever made. As yet, the 

 rich store of organic remains which the dark grey flagstones contained had not been 

 brought to light, but the stimulus given to this branch of investigation by the work of 

 Hugh Miller and Agassiz awakened interest in the subject, and we find that a number of 

 collections was formed, especially from the quarries in the neighbourhood of the town 

 of Stromness. Hence when, at a later period (1848), Hugh Miller paid a visit to this 

 district, as narrated in his Footprints of the Creator, or the Asterolepis of Stromness, 

 many of the fossils of these rocks were already well known to local collectors, among 

 whom he mentions particularly the late Mr W. Watt of Skaill and Dr Garson of Strom- 

 ness. Professor Traill of Edinburgh University had for many years been forming a 

 collection, and specimens had been forwarded by him to Agassiz, who makes mention of 

 the fact. Hugh Miller, in the work above cited, and in his Cruise of the Betsy (1858), 

 gives a description of his visit to Kirkwall, Stromness, and various parts of the West 

 Mainland, which contains many interesting facts relating to the occurrence and distribu- 

 tion of the fossils in these districts. Further reference to his work will be found in a 

 subsequent part of this paper. The general similarity of the rocks around Stromness to 

 the sandstones of Cromarty and the flagstones of Caithness, as regards the fossils they 

 ontained, may be regarded as well established at this date, and the subsequent descrip- 

 :ions of Orcadian specimens contained in Professor M' Coy's Synopsis of Classification of 

 British Palaeozoic Bocks (1858) served in some measure to confirm this opinion. So far, 

 :here had been no attempt to ascertain the structure of the county, but in 1858 Sir R. 

 uurchtson* made a brief survey of the islands. He ascertained that there were at least 

 wo main types of sedimentary deposits in the Old Red Sandstone of Orkney,— a lower 

 eries of flagstones and, overlying them, conformably, as he believed, a series of yellow 

 andstones, well seen in the island of Hoy. The lower series at Stromness rested, by 

 neans of a basement conglomerate, upon an axis of crystalline rock. A great advance 

 vas made in 1878 by the appearance of the first part of Sir Archibald Oeikie's mono- 



* Sir R. Murchison, Quart. Jour. Geol. Soc, vol. xv. 

 VOL. XXXIX. PART II. NO. 13). 3 N 



