THE OLD RED SANDSTONE. 231 
pial family ; and these, says Mr. Lyell, afford the only exam- 
ple yet known of terrestrial mammalia in rocks of a date an- 
terior to the older tertiary formations. The reptile seems to 
have preceded the bird, and the bird the mammiferous ani- 
mal. ‘Thus the feetal history of the nervous system in the in- 
dividual mammifer seems typical, in every stage of its prog- 
ress, of the history of the grand division at the head of 
which the mammifer stands. Agassiz, at the late meeting of 
the British Association in Glasgow, mentioned an analogous 
fact. After describing the one-sided tail of the more ancient 
fish, especially the fish of the Old Red Sandstone, — the sub- 
jects of his illustration at the time, —he stated, as the result 
of a recent discovery, that the young of the salmon in their 
foetal state exhibit the same unequally-sided condition of tail 
which characterizes those existences of the earlier ages of 
the world. The individual fish, just as it begins to exist, pre- 
sents the identical appearances which were exhibited by the 
order when the order began to exist. Is there nothing won- 
derfulin analogies such as these — analogies that point through 
the embryos of the present time to the womb of Nature, big 
with its multitudinous forms of being? Are they charged 
with no such nice evidence as a Butler would delight to con- 
template, regarding that unique style of Deity, if I may so ex- 
press myself, which runs through all his works, whether we 
consider him as God of Nature, or Author of Revelation ? 
In this style of type and symbol did He reveal himself of 
old to his chosen people ; in this style of allegory and para- 
ble did He again address himself to them, when he sojourned 
among them on earth. 
The chemistry of the formation seems scarce inferior in 
interest to its zoology; but the chemist had still much to do 
for Geology, and the processes are but imperfectly known. 
