Scientific Intelligence. 215 



The carbonate is found in veins along the adit, and descending below 

 it, and is mixed with sulphate of baryta, and some galena, but the prin- 

 cipal product of this part of the workings is the carbonate, which occurs 

 in such quantity as to become an object of mining industry. 



It is- sold, like the sulphate of the same earth raised in the upper 

 part of the vale of Clwyd, the Isle of Arran, and Renfrewshire, for the 

 avowed purpose of adulterating white paint, and is more difficult of de- 

 tection than the other adulteration, because it effervesces with, and is so- 

 luble in, muriatic or hydrochloric acid. It is also sold on a more limited 

 scale for chemical purposes. We have now, then, in Southern Britain, 

 five great localities of Carbonate of Baryta— Anglezark in Lancashire, 

 Aldstone Moor in Cumberland, Arkingarthdale or Arkindale in York- 

 shire, Snailbeach in Shropshire, and Rhualt in Flintshire. 



SCIENTIFIC INTELLIGENCE. 



1. Fossil Fishes of Orkney.— On Monday, 21st December, Dr 

 Traill exhibited to the Royal Society specimens of all the fossil 

 fishes collected by him from the old red sandstone formation of 

 the Orkney Islands. 



A part of this collection had been submitted to the Geological 

 Section of the British Association at Edinburgh, in 1834, when 

 they were examined by M. Agassiz, who not only found among 

 them new species, but new genera. Among them, he saw, for the 

 first time, the genus Diplopterus, which he has slightly noticed in 

 his work. The characters of this genus are, "Two anal, equal 

 and opposite to two dorsal, fins ; tail with nearly equal and even 

 lobes ; mouth large, and furnished with large conical teeth." The 

 size of the mouth and form of the tail distinguish it from Dip- 

 terus, which has a small head, and a deeply bifid tail ; and the 

 possession of two equal and opposite dorsal and anal fins distin- 

 guishes it no less from Osteolepis and Palaeoniscus. 



The species from which M. Agassiz established the genus has 

 not yet been published ; and as another species of Diplopterus has 

 lately been discovered in Scotland, and also, it is said, in Ireland, 

 Dr Traill, assuming the privilege usually allowed to the finder of 

 a new species, and desirous of connecting with his country the 

 name of the celebrated naturalist who has done so much to illus- 

 trate its fossil ichthyology, proposes to mark this Orkney species 

 as Diplopterus Agassis, a designation under which it has been 

 already sent to different geological collections. The number of 



