156 James Neilson — Old Bed and Carboniferous of Arran. 



of limestone full of true Carboniferous Limestone corals and 

 brachiopods." Again (p. G(J5), be draws our attention to tbe 

 statement tbat " In Australia a flora witb Jurassic affinities and 

 a Carboniferous Limestone fauna were contemporaneous " ; while 

 we may conclude our extracts by one wbicb says: "At the present 

 day tbe higher fauna of Australia is more nearly akin to tbat which 

 flourished in Europe far back in Mesozoic time, than to the living 

 fauna of any other region of the globe." 



Tbe above quotations and extracts show the way in which 

 palaeontological evidence may be treated by those who strictly 

 follow Prof. Huxley's views on homotaxis ; and without offering 

 any opinion on other matters, I propose to proceed to the con- 

 sideration of tbat part which concerns the West of Scotland, viz., 

 the question whether marine Carboniferous Limestone fossils are 

 found in Old Red Sandstone strata. 



Again, I quote (p. 801) from the chapter on Old Red Sandstone : — 

 " In the Upper Old Red Sandstone of the Firth of Clyde Bothriolepis 

 (Pterichthys) major and Holoptychius occur at the Heads of Ayr; 

 while a band of marine limestone, lying in the red sandstone series 

 of Arran, is crowded with ordinary Carbon ifei'ous Limestone shells, 

 such as Productvs gigantens, P. semireticidatus, P. punctatus, Chonetes 

 hardrensis, Spirifer linen tits, etc. Tbese fossils are absent from the 

 great series of red sandstones overlying the limestone, and do not 

 reappear till we reach the limestones in tbe Lower Carboniferous 

 series ; yet the organisms must have been living during all that 

 long interval outside of the Upper Old Red Sandstone area. Not 

 only so, but they must have been in existence long before tbe 

 formation of the thick Arran limestone, though it was only during 

 the comparatively brief interval represented by the limestone that 

 geographical changes permitted them to enter the Old Red Sand- 

 stone basin and settle a while on its floor. The higher parts of the 

 Upper Old Red Sandstone seem thus to have been contemporaneous 

 with a Carboniferous Limestone fauna, which, having appeared 

 beyond the British area, was ready to spread over it as soon as 

 the conditions became favourable for the invasion. It is, of course, 

 obvious that such an abundant and varied fauna as that of the 

 Carboniferous Limestone cannot have come suddenly into existence 

 at the period marked by the base of the limestone. It must have 

 had a long previous existence outside the area of the deposit." 



Sir Archibald Geikie also returns to the subject when treating of 

 tbe Carboniferous system, thus (p. 828) : " Hence it is evident that 

 the Carboniferous Limestone fauna had already appeared outside 

 the British area before tbe final cessation of tbe peculiar conditions 

 of sedimentation of the Old Red Sandstone period." 



The fact is, that no Old Red Sandstone fishes have been 

 recorded, and, so far as we are aware, none have ever been found 

 in Arran. The fishes referred to by Geikie were, I presume, those 

 from the Red Sandstone south of the Heads of Ayr, on the mainland 

 of Scotland, some twenty miles distant from the Arran limestone. 



Arran is classic ground to the geologist, and its fame has travelled 



