80 
The Presidential Address. 
further reflect upon the vicissitudes to which fossiliferous 
strata are and have been at all times exposed by denudation, 
erosion, and metamorphism, it appears to me that there is 
not much matter for marvel in this poverty of the geological 
record, but rather that we should wonder at its comparative 
richness. In fact the geological record, however imperfect it 
may be, has furnished the very strongest evidence in favour 
of the Darwinian theory, and since the year 1859 the progress 
of Palaeontology has enabled many gaps between the most 
diverse groups of animals to be filled up. What more distinct 
in external form and mode of life than birds and reptiles ? 
These two classes had, however, long been known to 
anatomists to be structurally related, and on the principle of 
evolution the existence of intermediate forms might have 
been anticipated. In 1862, after Darwin had predicted the 
existence of such connecting links, 16 there was found in the 
Solenhofen limestone of the Upper Jurassic series, in Bavaria, 
the now well-known Archceopteryx, an animal uniting the 
characters both of birds and reptiles. Professor Huxley sub¬ 
sequently pointed out that a family of extinct gigantic reptiles, 
the Dinosauria of the Oolite and Cretaceous formations, pre¬ 
sented certain distinctly avian characters. These discoveries 
culminated, in 1875, in Professor Marsh’s great find of 
toothed birds, the Odontornithes of the Cretaceous beds of 
Kansas, 17 a discovery which, as Professor Huxley says, 
“removed Mr. Darwin’s proposition that ‘ many animal 
forms of life have been utterly lost, through which the 
early progenitors of birds were formerly connected with the 
early progenitors of the other vertebrate classes,’ from the 
region of hypothesis to that of demonstrable fact.” 18 In a 
similar manner the pedigree of the horse has been traced 
back by Professor Marsh to the Eocene species of Eohippus , 19 
an animal about the size of a fox ; and the pedigrees of the 
16 ‘ Origin,’ 1st ed., p. 431. 
17 Vol. i., ‘Memoirs of Peabody Museum of Yale College’; vol. vii., 
“ Geological Exploration of tire 40tli Parallel.” 
18 “ The Coming of Age of the ‘Origin of Species,’ ” ‘ Nature,’ May 6th, 
1880, p. 3. 
19 Amer. Jour. Sci., 1879. 
