GEOGNOSY AND GEOLOGY. 137 
19. Improvement of Organic Forms with the Increasing Age of the 
Earth. 
A little attention to the succession of organisms, as presented by 
fossiliferous strata, will soon convince us of a progressive improvement and 
perfection of forms. The most imperfect are found in the oldest strata, 
and the higher they occur in any formation, the higher the degree oi 
their organization. By this, however, it is not meant that plants existed at 
first alone, and that after they had attained their highest degree of 
development, then the lowest animals made their appearance, but rather 
that the development of the animal and vegetable world took place in two 
parallel series. The oldest plants and animals stand so closely together, 
that im many cases it puzzles the most skilful paleeontologist to decide when 
any given fossil belongs to one or the other. 
Neither must we be understood as affirming that the plants and animals, 
as they at present occur, are the result of an actual development of the 
lower forms into the higher, the noblest forest trees proceeding by insensible 
gradations from the minute cryptogamia, and man from the monad. We 
simply mean that in successive creations, at successive epochs, the new 
forms were of more highly organized character than the old. And while 
the general fact may be as just expressed, there are many special 
exceptions, numerous instances existing where there appears to have been 
an actual retrogression. Thus at one time the seas of Europe swarmed 
with enaliosaurians of immense size and high organization; the Ichthyosaurus 
and Plesiosaurus devastated the marine regions which they inhabited. Yet 
all traces of this high order of reptilia have vanished from our existing 
fauna, unless the far-famed sea serpent be a representative, as has been 
suggested by some zoologists. The gigantic Dinosaurians, too, have 
vanished; and of the once extensive order of Crocodilians, only a few 
imperfect forms remain here and there on the surface of the earth. 
The oldest plants were probably those belonging to the land, water 
plants being found long after; that is, im much more recent strata. The 
case was different with animals, the oldest having been marine. 
In the oldest formations acotyledonal plants come first, and then 
monocotyledonal; a few dicotyledons next occur, subsequently to present 
themselves in greater number. 
Among animals corals are found first, then radiata and crustacea, and 
afterwards fishes. Mollusca and radiata then occur more abundantly, and 
in enermous quantity, and afterwards the most extraordinary and gigantic 
reptilia. Subsequently we find mammalia, more rarely birds. Human 
remains occur only in formations of our era, and which are going 
on at the present time. 
567 
