32 CEOLOGY. 



ment, it is made ir> of three principal divisions. The oldest (Bunter) 

 and youngest (Keuper) divisions consist of beds of fragmental rock, 

 including conglomerates, sandstones, and shales, separated by a for- 

 mation (Muschelkalk) of limestone. The oldest of these formations 

 was deposited chiefly in lakes, inland seas, and on the dry land, as 

 shown by the fossils, the beds of salt and gypsum, and the dune struc- 

 ture of the sandstone. 1 There are in some places cubes of sandstone, 

 the sand of which appears to have been originally included in crystals 

 of salt, as that mineral was precipitated from solution in inclosed 

 bodies of water. Subsequently the salt was dissolved, but replaced by 

 other cementing matter which preserved the cubes of sandstone. 

 Toward the upper part of the formation, thin beds of marine origin 

 are locally intercalated with those of non-marine origin, showing that 

 changes in the relation of land and water were in progress, and that 

 the sea gained on the land to some extent toward the close of the 

 epoch. Tracks of land reptiles are sometimes found on the layers 

 of shale and sandstone, showing that they were deposited on land 

 or in water sufficiently shallow to allow terrestrial animals to wade 

 in it. The tracks sometimes occur in layers which had been cracked by 

 drying at the time the tracks were made. This shows that the mud- 

 beds over which the reptiles walked were sometimes dry, and that 

 for periods sufficiently long to let the cracks develop.. The areas 

 where these phenomena occur may have been under water during 

 wet seasons, and dry at other times. 



The tracts where this formation comes to the surface are, on the 

 whole, not fertile, and have been allowed to remain in forests 

 extensively. So true is this, that the Bunter sandstone may be said 

 to be the " forest formation" of western Germany. The name (Bunter) 

 has reference to the brilliant colors displayed by the formation. Red 

 predominates, but other colors are not absent. The Bunter sand- 

 stone of the Eifel carries galena in small grains and lumps, and the 

 Romans mined it. 2 



The second formation, the Muschelkalk, shows that the encroach- 

 ment of the sea recorded by the upper part of the preceding formation 

 had gone so far that the ocean held sway over much of the area where 



1 Kayser, Geologische Format ionskunde, p. 330. 



2 Ibid., p. 283. 



