OF THE CARBONIFEROUS SERIES. 638 



about, the same horizon ; those above the " .Bottom " vein have only 

 yielded remains of placoid and ganoid fishes. 



Prom a review of the fauna of the South- Wales Coal-field, Mr. 

 Salter drew the following amongst other inferences : — 



"1st. That there is a real distinction between the different beds 

 of ironstone in regard to their fossil contents, and that we may here- 

 after use these fossils for the purposes of identification. 



"2nd. That the lower beds of the Coal-measures in South Wales, 

 Lancashire, and Shropshire contain a set of marine fossils, some of 

 which are Mountain-Limestone species, and the rest peculiar to the 

 Coal-measures. 



" 4th. That the decidedly marine species diminish as we ascend 

 in the section ; and that their place is occupied by other (bivalve) 

 shells, Anihracomya, Modiola, Myalina ?, which must have been 

 inhabitants of salt, or at least highly brackish water, and that, as 

 the Anihracosice (the common " Unio or mussel bands") arc always in 

 company with these, they also must be marine (or brackish ?), and 

 not freshwater as commonly supposed. They were mud-burr owing 

 shells with wrinkled epidermis, like the Myadce "*. 



This eminent palceontologist did not live to complete the paiaeon- 

 tological examination of the British Coal-fields which he had so well 

 begun in South Wales, Staffordshire, and Lancashire. It yet remains 

 to be determined whether special horizons amongst the Middle Coal- 

 measures can be identified in different districts on fossil evidence. 



Part IV. 



Scottish Carboniferous Districts. 



Having now passed in review as many sections in England and 

 "Wales as seem necessary for my purpose, I proceed to examine the 

 Scottish series with a view to correlation with those in South Britain ; 

 and after a good deal of consideration I have come to the conclusion 

 that the following is a correct representation of the corresponding 

 series in both countries : — 



General Section of the Scottish Carboniferous Bech 

 (Central Valley of Scotland). 



Stage G. Upper Coal-measures, 200 feet.— Eed Sandstones and Cloys of Both- 

 well without coal-seams. This series in Ayrshire contains a seam of lime- 

 stone with Spirorbis, and rests unconformably on the beds underneath. 



Stage F. — "Upper or Flat Coal-measures" of Scotland. Sandstones, shales, 

 and clays, with coal-seams and ironstones. Fish -remains, Anthracosia, An- 

 thracomya, and Anthracoptera. A marine band occurs at Drum poller 

 about 60 feet above the "Ell coal"t. 



* Iron-ores of Great Britain. Part III. p. 234. 



t Described by Mr. Whyte Skipsey. The following occur — Productus sca- 

 briculus, Distinct, nitida, Conidaria, Bellerophcn Urii. This band maybe on the 

 horizon of the Chance Pennystone of Salop. 



