Classification of Roclcs, 13 



In this formation there are a number of shells of extinct species, about one 

 fourth of the whole, the other three fourths being of species now living in 

 the sea. There are found in this deposit also the remains of many large 

 quadrupeds, some of which still exist, but the great majority being extinct. 

 During this period nearly all Canada was submerged, and the ocean 

 which covered, it appears to have been full of icebergs. The rounded 

 boulders and great fragments of rock strewn about the fields of this 

 country are supposed to have been transported from the north by the 

 floating ice of the Pliocene ocean. 



4. Older Pliocene. — One third of the shells, and nearly, if not all the 

 mammalia, extinct. This formation occurs in Europe, but has not yet been 

 recognized in Canada. 



C. Miocene. 



5. Miocene. — All of the mammalia found in this group are of 

 extinct species. About two thirds of the mollusca are also extinct, and of 

 those which are still existing, many are not to be met with in the neighbour- 

 ing seas but on some coast more or less distant. The Miocene is not found 



in Canada. 



D. Eocene. 



The Eocene is thus divided : — G. Upper Eocene ; 1. Middle Eocene y 

 8. Lower Eocene. — None of these occur in Canada, they abound in Eng- 

 land, France, and various other parts of Europe. The fossil shells of the 

 Eocene period, with very few exceptions, are extinct. Those which belong 

 to existing species rarely found in the neighbouring seas. All the mam-" 

 malia are of extinct species, and for the greater part of extinct genera ; the 

 plants found in the upper Eocene of England and France indicate a South 

 European or Mediterranean climate — those of the lower Eocene, a tropical 

 climate. The above groups, B, C, and D, constitute the Tertiary forma- 

 tions. The word Pliocene is from the Greek, pleion, more ; and kainos, 

 recent : Miocene, is from meion, less ; and kainos, recent : Eocene, is eos, 

 morn or dawn ; and kainos, recent. The first name. Pliocene is applied to 

 formations more recent than all the others ; Miocene is not so recent as 

 Pliocene, while the Eocene was so called because it was during this period 

 that animals of existing species were supposed to have first made their 

 appearance. It was considered to be the dawn of the existing state of 

 tilings. A few recent species are, however, found still lower down. 



E. Cretaceous. 

 The Cretaceous rocks, commonly called Chalk Formations, are thus divid- 

 ed : — 9. Maestricht Beds ; 10. Upper White Chalk; 11. Lower IfTiite 

 Chalk; 12. Upper Greensand ; 13, Gault ; 14, Loicer Greensand ; 

 15. The Wealden. — The Chalk formations arc largely developed in Europe ; 

 a vast sheet of pure chalk several hundred feet in thickness extends in a 

 North-west and South-east direction from the North of Ireland to the Cri- 

 mea, a distance of about 1,140 geographical miles, and in an opposite direc- 

 tion from the South of Sweden to the South of Bordeaux, a distance of 

 •^bout 840 geographical miles. In North America the Cretaceous rocka 



