338 
ELEMENTS OF GEOLOGY* 
Fig, 321. 
Tail and feather of Archoiopteryx, from SoleuhofeDj and tail of living bird for 
comparison. 
A. Caudal vertebrae of Archmopteryx maxrufa^ Owen ; with impression of tail-feath¬ 
ers; one-fifth natural size. B. Two caudal vertebrae of same; natural size. C. 
Single feather, found in 1861 at Solenhofen, by Von Meyer, and called Archmo¬ 
pteryx lithographica; natural size. D, Tail of recent vulture {Gyps Bengalemis) 
showing attachment of tail-feathers in living birds; one-quarter natural size. E. 
Profile of caudal vertebrae of same; one-third natural size, e, e. Direction of tail- 
feathers when seen in profile. /, Ploughshare bone or broad terminal joint (seen 
also in/, D.) 
Professor Huxley in his late memoirs on the order of rep¬ 
tiles called Dinosaurians, which are largely represented in all 
the formations, from the Neocomian to the Trias inclusive, has 
shown that they present in their structure many remarkable 
affinities to birds. But a reptile about two feet long, called 
Compsognathus, lately found in the Stonestield slate, makes 
a much greater approximation to the class Aves than any 
Dinosaur, and therefore forms a closer link between the 
classes Aves and Reptilia than does the Archmopteryx. 
It appears doubtful whether any species^ of British fossil, 
whether of the vertebrate or invertebrate class, is common 
to the Oolite and Chalk. But there is no similar break or 
discordance as we proceed downward, and pass from one to 
another of the several leading members of the Jurassic 
group, the Upper, Middle, and Lower Oolite, and the Lias, 
there being often a considerable proportion of the mollusca, 
sometimes as much as a fourth, common to such divisions 
as the Upper and Middle Oolite, 
