278 FOSSIL FISHES, 
Fishes ill Strata of the Carboniferous Order, 
I select the genus Amblypterus (PI. 27^.), 
as an example of Fishes whose duration was 
limited to the early periods of geological Forma- 
tions ; and which are marked by characters that 
cease after the deposition of the Magnesian 
limestone. 
This genus occurs only in strata of the Carbo- 
niferous order, and presents four species at 
Saarbrlick, in Lorraine ;* it is found also in 
Brazil. The character of the teeth in Amblyp- 
terus, and most of the genera of this early epoch, 
shews the habit of these Fishes to have been 
to feed on decayed sea-weed, and soft animal 
substances at the bottom of the water : they are 
all small and numerous, and set close together 
like a brush. The form of the body, being not 
calculated for rapid progression, accords with 
this habit. 
* The Fishes at Saarbrlick are usually found in balls of clay 
ironstone, which form nodules in strata of bituminous coal shale. 
Lord Greenock has recently discovered many interesting ex- 
amples of this, and other genera of Fishes in the coal formation 
at Newhaven, and Wardie, near Leith. The shore at Newhaven 
is strewed with nodules of ironstone, washed out by the action of 
the tide, from shale beds of the coal formation. Many of these 
ironstones have for their nucleus a fossil Amblypterus, or some 
other Fish ; and an infinitely greater number contain Coprolites, 
apparently derived from a voracious species of Pygopterus, that 
preyed upon the smaller Fishes. 
