Reviews — Scottish Carboniferous Rocks. 83 



form substantial contribntions to onr knowledge, " there is abundance 

 of room," as Dr. Traquair observes, for further investigation. 



In dealing with the Carboniferous fish-remains of tlie Edinburgh 

 district, Dr. Traquair remarks on the general similarity in the 

 lithological characters and in the fades of the organic remains of 

 the Scottish strata, which in mass are of estuarine origin. Elsewhere 

 in Britain the Upper Carboniferous rocks are also mainly of 

 ' estuarine ' or ' lagoon ' formation, but the Lower, except in the 

 extreme north of England, are almost as exclusively marine in their 

 origin; and in this grouping Dr. Traquair takes the Millstone Grit as 

 the base of the Upper division. His researches, which have extended 

 over a period of thirty years, show that in the Edinburgh district 

 different assemblages of estuarine fishes characterize the two Car- 

 boniferous divisions. Indeed, it is remarkable that not one of the 

 species from the Upper Carboniferous rocks "can safely be identified 

 as occurring in the rocks below ; we have evidently got into quite 

 a new ichthyological stage." 



Further^ the Lower Carboniferous fish-remains found in the 

 limestones of open-sea origin differ from those occurring in the 

 estuarine beds, and belong to the marine fish-fauna characteristic 

 of the Mountain Limestone of England and Ireland. Rarely is 

 there any commingling of these types of fishes. At the same time 

 the number of marine species is greater and of estuarine species 

 less in the Lower Carboniferous series of Lanarkshire and Ayrshire, 

 ■than in the rocks of the Lothiaiis and Fifeshire. 



Turning to the evidence obtained in other areas, Dr. Traquair 

 points out that, whether in Northumberland, Yorkshire, or North 

 Staffordshire, nearly all the common Upper Carboniferous estuarine 

 ■fishes have a wide range in the Coal-measures, so that " it is 

 not possible to divide these strata into ichthyological life- zones." 

 Elsewhere also he finds a great difference between the species which 

 occur below and above the Millstone Grit. " Only two species can 

 with certainty be named as common to the two divisions, namely, 

 Callopristodtts pectinntus and Acrolepis HopTcinsi." 



In the Scottish Millstone Grit no determinable fish-remains have 

 been found, but among the fishes recorded by Mr. E. D. Wellburn 

 from this division in Yorkshire and Lancashire, thei'e are both 

 Lower Carboniferous marine species and Upper Carboniferous 

 estuarine species. The occurrence of the latter in the Millstone 

 Grit coincides with the evidence of the plants, which according to 

 Mr. Kidston " are entirely Upper Carboniferous in aspect." 

 Dr. Traquair is thus led to ask, "Did the marine fish-fauna of the 

 Carboniferous epoch change less rapidly than that of the estuaries 

 and lagoons? " 



The fact, however, remains that a great and wide-spread change 

 took place in the fish-fauna at about the time of the Millstone Grit. 



Dr. Traquair directs attention to a peculiar fish-fauna in the 

 estuarine Lower Carboniferous beds of Eskdale. At Glencartholm, 

 near Langholm, more than thirty species of fishes have been obtained, 

 and of these only one, TristycJiins minor, is found in the Lower 



