THE STORY OF THE EARTH 



might be expected. Nor does any break occur 

 between the upper limit of the fresh water old 

 red sandstone and the marine carboniferous rocks 

 in the Welsh country. The carboniferous rocks 

 arc- usually conformable from top to bottom; but 

 there is sometimes an unconformable succession 

 of Millstone grit upon mountain limestone, in the 

 Forest of Dean. There is a great unconformity 

 between the Carboniferous rocks and the Per- 

 mian. This makes a total of ten physical breaks 

 which are evidenced during the primary portion 

 e< logical time. 



There is a complete stratigraphical break, or 

 unconformity between the Trias and the Permian. 

 Near Ormskirk the new Red Marl rests uncon- 

 formably on the new Red Sandstone. There is 

 no visible unconformity between the Kinetic beds 

 and the Lias, which rests upon them, but the 

 Change in life indicates a great break in the 

 Uniformity of previous conditions. There is no 



complete unconformity between the l ias and the 

 overlying Inferior Oolite. But the change in life 



to this deposit, and through all the SUCCeed 



divisions of the Oolites, is such as may 1 



ciated with unconformity in adjacent anas. At 



the top of the Oolites there is an insensible pas- 



e from the marine Portland limestone to the 



Purbeck beds. But since the Puibeck deposits 



include terrestrial surfaces, and are largely of 



, -water origin, an unconformity must exist 

 in the south of England in this part of the siic- 



l he wealdcn beds may also be uncon- 

 formable B I in the overlying creta* eries 



* mi. onformity is an 



rlap on tin- older str.tt. i which gave increased 



geographical extension to the Hunstanton lime- 



