Fossil Fishes. 53 



" If vve regard the whole organized beings which have lived si- 

 multaneously with the Heteroceric Lepidoidians. or those with un- 

 symmetric tails, we shall remark that they were for the most part 

 fixed at the bottom of the waters, or at least that they crawled about 

 there, without being able to elevate themselves freely and at their 

 wills towards the surface, and move about at large. With the ex- 

 ception of some reptiles, the appearance of which on the earth was 

 much posterior to that of fishes, all these animals were aquatic, and 

 the soil bore only those plants which are analogous to those of great 

 archipelagoes or of low plains. Fish, therefore, were the first of 

 the animals to which the power was given of spontaneously gliding 

 through space in all directions, in water ; whilst the movements of 

 the Crustacea were only irregular and imperfect. Among the Mol- 

 lusca, the Cephalopodes, which have the most power of motion, as- 

 cended to the surface of the water, and remained, the sport of the 

 winds in their aquatic ascensions ; the Gasteropodes were still more 

 bound to the soil, and the Acephales and Brachiopodes were fre- 

 quently fixed to it. All the Polypi and Crinoidians of that period 

 appear to have been attached by their base to different solid bodies. 

 At the same time, even the fishes, with their unsymmetrical tails, 

 could not execute' the accurate movements of the symmetrical fishes 

 of the following epoch, and their progressive movements therefore 

 would be still irregular. The whole of these animals respiring by 

 branchiae, could as yet utter no cry, and lived in the most absolute 

 silence. A long period assuredly elapsed ere the surface of the earth 

 was replenished with birds and beasts, and ere man could reflect 

 upon the events which have produced these changes in organic life. 

 We can scarcely conceive that, suiTounded with such facts as these, 

 it would be possible to doubt that there was a regular order of suc- 

 cession, and a constant progression in the work of creation." 



