236 ELEMENTS OF OENITHOLOGY. 



of the Tnassic, Jurassic, and Cretaceous formations. To the 

 " Triassie " formation belongs the stratum known as the New 

 Bed Sandstone. The " Jurassic " formation includes the Lias, 

 the Oolite, and Solenhofen Slates of Bavaria. The " Cretaceous " 

 formation comprises the Wecdden, tlie Lower and Upper Green^ 

 sand, the Qault, and the Chalk. The " Cainozoic or Tertiary " 

 rocks are composed of three " formations " — the Eocene, 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 " Orag." 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 Eblations oe Bieds. 



No remains or traces of Birds have yet been discovered in 

 any of the primary or Palaeozoic strata. 



Certain " moulds " in the form of footprints were long ago 

 (in ]831) found in Triassie 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 Ornitholite, was found 

 in 1861, in the Jurassic formation, namely, in the Solenhofen 

 Slate of Bavaria. This Bird is the now celebrated Archceopteryx, 

 which, though provided with long feathers, differs greatly from 

 any other Bird yet known. It was about the size of a Eook, 



