3i8 Evolution and Distribution of Fishes 



The appended list of the "Fossil Fishes collected by the 

 Geological Survey of Scotland in Eskdale and Liddesdale" 

 is eminently typical of the fish associations, as well as of 

 the Lower Calciferous strata that yielded them. It per- 

 mits their correlation also with fishes of other strata. 



LIST OF FISHES (From Trans. Roy. Soc. Edin. 30 [1883] 15). 



Eskdale Liddesdale 

 Acanthodidae 



1 Acanthodes sp * 



Rhizodontidae 



2 Strepsodus sauroides * * 



3 Archichthys portlocki ? * 



Saiirodipteridae 



4 Megalichthys sp * * 



Coelacanthidae 



5 Coelacanthus lepturus * 



6 * Coelacanthus huxleyi * 



Palaeoniscidae 



7 * Elonichthys serratus * 



8 * Elonichthys pulcherrimus * 



9 Rhadinichthys geikiei * 



10 * Rhadinichthys delicatulus * 



11 * Rhadinichthys macconochii * 



12 * Rhadinichthys tuberculatus * 



13 * Rhadinichthys angustulus * 



14 * Rhadinichthys fusiformis * 



15 * Cycloptychius concentricus * 



16 * Phanerosteon mirabile * 



17 * Holurus parki * 



18 * Holurus fulcratus * 



19 * Canobius ramseyi * 



20 * Canobius elegantulus * 



21 * Canobius pulchellus * 



22 * Canobius politus * 



Platysomidae 



23 Eurynotus crenatus * 



24 * Eurynotus ? aprion * 



25 Wardichthys ? cyclosoma * * 



26 * Cheirodopsis geikiei * 



27 * Platysomus superbus * 



Tarrasiidae 



28 * Tarrasias problematicus * 



Since the great majority of the species belonging to 

 the above genera have been found across central Scotland, 

 and since Cheirolepis is from Scottish rocks also, such sug- 

 gest that primitive Chondrosteans evolved in the area ex- 

 tending from N. Britain to W. Russia. But that they 

 spread fairly rapidly westward into Canada is shown by 

 the earlier descriptions of Dawson, (8^), also more re- 

 cent papers by him and by Lambe (97: i). Dawson in 

 describing five new species of Rhadinichthys says, "The 



