6 ELEMENTS OF ORNITHOLOGY, “ 
ios) 
of the Triassic, Jurassic, and Cretaceous formations. To the 
“Triassic” formation belongs the stratum known as the New 
Red Sandstone. The “Jurassic” formation includes the Lias, 
the Oolite, and Solenhofen Slates of Bavaria. The ‘“ Cretaceous 
formation comprises the Wealden, the Lower and Upper Green- 
sand, the Gault, and the Chalk. The “ Cainozoie or Tertiary ” 
rocks are composed of three ‘formations ”—the Locene, the 
Miocene, and the Pliocene. The oldest or “* Eocene ” formation 
underlies both Paris and London, and exists as very important 
deposits in North America. The ‘ Miocene” formation is 
widely distributed in Europe and the North-American conti- 
nent, but is very slightly represented in Britain. To it, 
however, belong the rocks which form the Giant’s Causeway 
and the islands of Staffa and Mull with others. The Pliocene 
formation is extensively distributed in Europe, Asia, and the 
United States. In England it is represented by the Norfolk 
and Suffolk ‘* Crag.” The later Pliocene rocks—which are often 
called Quaternary strata—include the deposits found in the 
ancient caves of Europe, and those thrown down during what 
is known as the Glacial epoch. That a period of intense cold 
prevailed in geologically recent times, over Northern and Central 
Europe and the greater part of North America, is shown by 
the evidences of “prodigious glaciers, which have scooped out 
valleys, and grooved and scored the surface of hill and dale 
in those regions, Blocks of stones, called “ boulders,” are often 
found scattered about, and seem to have been transported by 
ice, sometimes from very great distances, 

GEOLOGICAL RELATIONS OF BiRDs. 
No remains or traces of Birds have yet been discovered in 
any of the primary or Paleozoic strata. 
Certain ‘‘moulds ” in the form of footprints were long ago 
(in 1831) found in Triassic deposits in Connecticut, but these 
are now believed to have been made by certain extinct, in many 
respects bird-like, reptiles. 
The oldest undoubted Bird-fossil, or Or "nitholite, W was found 
in 1861, in the Jurassic formation, namely, i in the Solenhofen 
Slate of Bavaria. This Bird is the now celebrated Archwopterya, 
which, though provided with long feathers, differs greatly from 
any other Bird yet known. It was about the size of a Rook, 
