116 DR RAMSAY H. TRAQUAIR ON FOSSIL FISHES COLLECTED BY 



bottom of the fish-bearing series" (p. 701). And I have shown that while some species 

 like Nematoptychius Greenocki and Eurynotus crenatus persist from bottom to top of 

 these estuarine fish-bearing rocks, some have as yet only occurred in the lower, others 

 in the upper, horizons as usually adopted. 



If, then, fish-remains are to count in the determination of the horizon of the Gullane 

 beds, I would point out that their fish-fauna show the greatest amount of agreement 

 with that of the Wardie Shales of all the horizons in the Lower Carboniferous of 

 Central Scotland in which fishes have been found. 



Finally, we have seen that out of eleven named Gullane species, eight occur at 

 Wardie. What of the other three, which have not been found in any other locality near 

 Edinburgh ? 



Of these, one is peculiar to the East Lothian locality, namely, Rhadinichthys 

 formosus. 



The remaining two, namely, Elonichthys striatulus and Rhadinichthys elegantulus, 

 form part of the peculiar Lower Carboniferous fish-fauna of Glencartholm, on the Eiver 

 Esk, near Langholm. Two explanations of the peculiarity of this fish-fauna have been 

 suggested, — either the existence of a land barrier, or a difference in horizon, these 

 Eskdale beds being supposed to be of older date than the Granton and Craigleith 

 Sandstones. The latter explanation does not seem probable in the face of the fact 

 that such well-known Central Scottish species as Or acanthus armigerus, Traq., and 

 Tristychius minor, Port!., have also been found at Glencartholm, while the determina- 

 tion of two further species as common to the last-named locality and Gullane is further 

 evidence against the idea, so far as fishes are concerned. If, however, the existence of 

 a land barrier was the cause of the phenomenon in question, it is clear that it was not 

 sufficient to prevent the intermixture of species to a certain extent. The Glencartholm 

 beds were certainly not deposited in a land-locked lake at all events, as the occurrence 

 of numerous marine shells in them amply testifies. The further development of the 

 subject I must leave to the Officers of the Geological Survey. 



EXPLANATION OF THE PLATES. 



[All the figures are taken from specimens from Bed a, Gullane, except fig. 5 on Plate I., which 

 illustrates a specimen from Glencartholm, near Langholm, Eskdale.] 



Plate I. 



Fig. 1. Elonichthys Rohisoni (Hihhert). Natural size. Gullane. (Geol. Surv. Scot., M 293 f.) 



Fig. 2. Elonichthys stria/ utus, Traq. Natural size. Same locality. (Geol. Surv. Scot., M 4409 E.) 



Fig. 3. Flank scales of the above specimen, magnified 12 diameters. 



Fig. 4. Caudal scale from the same, magnified 12 diameters. 



Fig. 5. Elonichthys striatulus. Traq. Natural size. From Glencartholm, Eskdale, in the Royal 

 Scottish Museum. 



Fig. 6. Rhadinichthys formosus, Traq., distorted by "shortening up" of the anterior part of the body. 

 Natural size. Gullane. (Geol. Surv. Scot., M 292 f.) 





