EARLIEST TYPES OF ANIMALS. 35 



we can look for upon earth, for the future, must consist 

 in the development of man's intellectual and moral 

 faculties. 1 



The question has been raised of late, how far the oldest 

 fossils known may truly be the remains of the first inha- 

 bitants of our globe, No doubt extensive tracts of fos- 

 siliferous rocks have been greatly altered by plutonic 

 agencies, and their organic contents so entirely destroyed 

 and the rocks themselves so deeply metamorphosed, that 

 they now resemble eruptive rocks more closely than 

 stratified deposits. Such changes have taken place again 

 and again up to comparatively recent periods, and upon 

 a very large scale, Yet there are entire continents North 

 America, for instance in which the palseozoic rocks have 

 undergone little, if any alteration, and where the remains 

 of the earliest representatives of the animal and vegetable 

 kingdoms are as well preserved as in later formations. In 

 such deposits, the evidence is satisfactory that a variety 

 of animals belonging to different classes of the great 

 branches of the animal kingdom has existed simulta- 

 neously from the beginning ; so that the assumption of a 

 successive introduction of these types upon earth is flatly 

 contradicted by well established and well known facts. 2 

 Moreover, the remains found in the oldest deposits are 

 everywhere closely allied to one another. In Eussia, in 

 Sweden, in Bohemia, and in various other parts of the 

 world, where these oldest formations have been altered 

 upon a more or less extensive scale, as well as in North 

 America, where they have undergone little or no change, 

 they present the same general character, and that close 



1 AGASSIZ (L.), An Introduction to versity and Number of Animals in 

 the Study of Natural History; New Geological Times; Amer. Journ. of 

 York, 1847, 8vo., p. 57. Science and Arts, 2nd ser., vol. 17, 



2 AGASSIZ (L.), The Primitive Di- 1854, p. 309. 



D 2 



