464 



THE GEOLOGIST. 



groupings of tlie Carboniferous deposits that have from time to time 

 made tlieir appearance in different works. 



In the valley of the Leven and Strath Endrick the one formation 

 passes gTadually into the oth-er without any seeming change in the 

 angle of dip, so that it is scarcely possible to draw a line between 

 the two systems ; and it is well known that the late Professor 

 Fleming has often expressed a similar opinion. 



It is not, however, the object of the present paper to discuss any 

 geological questions, and far less the age or affinities of the Old Red 

 sandstone ; but we will conclude the little we have thought neces- 

 sary to mention by a short extract taken from the last edition of 

 " Siluria," wherein the author has stated that " the Old Red sand- 

 stone in Lanarkshire is of comparatively small dimensions, from the 

 great masses of rock which constitute the central and superior mem- 

 bers of the group in the north-east of Scotland being there omitted, 

 and that it has not afforded any characteristic organic remains ; that 

 it is only in certain reddish and yellowish sandstones and shales, as 

 seen in Fifeshire, the Lothians, and particularly in Ayrshire, that the 

 geologist can be said to enter among those strata which here and 

 there are linked on the Carboniferous rocks above, as they unques- 

 tionably are to the Old Red sandstone below, and which, according 

 to the predominence of their fossil contents, may be grouped with 

 either deposit, like the tilestones which connect the Upper Silurian 

 with the true transition-beds which unite the Old Red with the Car- 

 boniferous series." 



No Brachiopoda have been found in these Old Red sandstone beds 

 of Scotland.* 



For general and detailed information concerning the geology of 

 the Carboniferous systems we must refer the reader to the well- 

 known works of Sir R. Murchison, Professor Philhps, General Port- 

 lock, Sir R. Griffith, Mr. Kelly, and of many other geologists ; it 

 being sufficient for our present pm^ose to notice that, although the 

 system has been somewhat differently subdivided in England, Scot- 



* Dovm the river Kildress, in Ireland, General Portlock and Mr, Kelly have 

 shown that under the calciferous or calcareous slates there occurs extensive 

 alternations of yellowish and reddish sandstones, then a bed of Hmestone, and 

 still lower down another band of red sandstone, replete AAi.th the most common 

 fossils of the carboniferous period, such as Athyris amhigua, Spiriferina octo- 

 plicata, Rhynchonella pleurodon, Streptorhynchus crenistyia, etc. Irish geologists 

 have rightly considered these strata as constituting the lowest diA-ision of the Cai'- 

 boniferous system, and they would be there in all probability some of the equi- 

 valents of those strata which Sir R. Mui'chison has mentioned as occurring in 

 Fifeshire and in Ayi'slui'C, and wliich he considers to form the transition-beds 

 between the Carboniferous and Old Red systems ; but with this difference, that 

 in Ireland the red and yellow sandstones are full of fossUs, while none appear to 

 have been hitherto discovered in the corresponding Scottish strata, although the 

 same species have been found higher up in the system. It is, therefore, ques- 

 tionable whether Irish geologists are justified wliile applving to this lower red and 

 yellow division of the Cai-bouiferous series the appellation of " Old Red sand- 

 stone," in making it a plea for annulling the Devouiau system in toto. 



