MALCOLMSON OLD KED SANDSTONE. 351 



found in the same situation. At several places near Stromness 

 galena occurs in considerable quantity, associated with heavy-spar 

 and stromnite, in what seems to be a line of fracture. At Scalpa 

 Bay also, two miles south of Kirkwall, veins of quartz and heavy- 

 spar occur along with iron- and copper-pyrites. Near KirkwaU I 

 collected many specimens of a delicate bivalve shell, in general form 

 like a Gyclas, but which does not possess characteristic generic 

 marks. Along with these were some large scales of fishes, and at 

 no great distance many fragments of the Goccosteus, some of them of 

 very large size, and others which had belonged to very young 

 animals. The above are the only shells yet found in the Old Eed 

 Sandstones of Scotland, and were pointed out to me by Mr. Kobertson 

 of Inverugie House, who collected them there some years before. 



Near the Manse of Hoy, in the island of the same name, I found 

 characteristic fish-scales and plants in the bituminous flags, not far 

 from a vein of red haematite, formerly worked ; and in the Dwarfie's 

 Glen this black schist graduates into as oft red freestone, on which 

 lofty cliffs of friable white sandstones, containing a few quartz - 

 pebbles, rest. At the Kaim, on the N.W. shore of the island, this 

 sandstone rests directly on the fish-beds ; and at Braeburgh, an in- 

 accessible ancient fortification, they form a perfectly vertical cliff, 

 risiag 900 feet from the ocean. Erom the very edge of this frightful 

 precipice, I collected fine specimens of black oxide of manganese, 

 which occurs in botryoidal veins, probably of contemporaneous forma- 

 tion with the sandstone. Dykes and great masses of amygdaloidal 

 trap, abounding in nests of calc-spar, occur at the base of these cHifs, 

 and near the Long Hope at the other end of the island. 



On the opposite shore of the Pentland Frith, the same sandstones 

 occur at Dunnet Head, resting on the bituminous flagstones of 

 Caithness, which abound in remains of fish and plants identical with 

 those of Lethen. At Huna and John o' Groat's House, I found fi^h- 

 scales and plants in the red sandstones immediately above the bitu- 

 minous flags near Duncansby Head, to the very summit of which 

 the black shales with Ichthy elites have been elevated, — the yellowish 

 sandstones being thrown off to either side of that magnificent head- 

 land. On the whole, a very careful examination of this coast left 

 little reason to doubt that these headlands belong to the series of 

 sandstones interposed between the lower fish-beds and those of the 

 central or Cornstone division of the Old Red system*. 



* In a new flagstone-quarry a httle to the south of the celebrated ichtliyoHtic 

 deposit of Banniskirk, I found plants identical with those of Lethen, Gamrie, 

 &c. These plants are also found in abundance near Barrogill Castle and 

 Castletown, associated with the usual genera of fish. 



VOL. XY. PART I. 2d 



