THE OLD RED SANDSTONE OF THE ORKNEYS. 387 



Magnus Spence of Deerness, who forwarded a specimen he found in Newark Bay to Dr 

 Traquair. To these we must add a new and undescribed species of Asterolepis, of which 

 scattered plates were found by Mr Spence of Deerness and myself in Deerness, Holm, 

 and South Ronaldshay. These have been presented by us to the Edinburgh Museum 

 of Science and Art, and Dr Traquair has kindly consented to draw up and publish a 

 description of them. This interesting fossil is, so far as we know at present, confined to 

 a narrow belt of the flagstones immediately underlying the Eday sandstones, where it 

 occurs with Dipterus valencienesii (Sedgwick and Murchison), and Glyptolepis 

 paucidens (Ag.) ; and should further investigations confirm this restricted distribution, 

 it may eventually be taken to mark the existence of a palseontological sub-zone im- 

 mediately beneath that of Tristichopterus alatus (Egert). That already it should be 

 known from three localities widely separated, and in each case from precisely the same 

 horizon, shows that it can hardly be called a rare fossil in Orkney, and in the future 

 further specimens may be confidently expected to turn up should these beds be sub- 

 mitted to careful and extended investigation. With this exception, this list of fossils 

 contains none which is not of very general distribution throughout the whole thickness 

 of the Orcadian flags. 



But when, in the progress of the mapping, a layer of rocks occupying a somewhat 

 lower position was reached, fossils were obtained which were new to Orkney, or among 

 the very rarest of those recorded from it. In the island of Rousay I found along the 

 west side a belt of rocks containing Coccosteus minor (Miller), the best specimens being 

 obtained in a quarry of thin slaty flagstones near Sacquoy Head. With it occurred the 

 large enamelled scales of a ganoid fish, of which the fragmentary remains were not 

 sufficient for satisfactory determination. Application was made to the proprietor of the 

 island, General Burroughs, for liberty to quarry, and permission was at once granted. 

 Better material was thus procured, and all doubt removed by the discovery of well pre- 

 served remains of Thursius pholidotus (Traquair), an addition to the list of the fossil 

 fishes of Orkney. Both occurred on the same bed of rock, and are here recorded from 

 Orkney, one for the first time, the other after a lapse of almost forty years, during which 

 the knowledge of its occurrence seems practically to have disappeared. Curiously 

 enough, when, at a subsequent time, at my request, Dr Traquair examined for me 

 certain plates of Coccosteus minor (Miller) preserved in the British Museum,* which, I 

 presumed, had come from another locality mentioned by Hugh Miller, he informed 

 me that these specimens, which belonged to the Egerton Collection, were derived from 

 the same locality, but when or by whom they were collected is not known. A very 

 careful search, a year or more previously, among all the local collections of fossil fishes, 

 had failed to bring under my notice any remains of this fish, and none seem to have 

 passed through Dr Traquair's bands, as he comments on its apparent absence from the 

 Dorth side of the Pentland Firth, t 



* A. Smith Woodward, B.M. Cat. — Fossil Fishes, pt. ii. p. 291. 

 t " Achanarras Revisited," Proc. Roy. Phys. Soc. Edin., xii. 285. 



