516 CARBONIFEROUS FISHES OF THE WEST OF SCOTLAND. 



It is true that a large proportion of the fishes of the Lower Carboniferous 

 rock& of this region are marine, while those of the true Coal-measures are 

 entirely estuarine, but in the East of Scotland, where those of the Lower 

 division are likewise mostly estuarine, almost as marked a difference obtains, 

 as regards species, though there is of course a greater similarity in general 

 facies. Consequently as we can there compare estuarine with estuarine 

 forms, the break in the Carboniferous fish-fauna which occurs at the top of 

 the Upper Limestone series is, as I have already remarked, brought home to 

 us with all the greater force. 



