THE JURASSIC PERIOD. 



75 



of the system the name of the White Jura. Some of the sandstones 

 also are white. 



One of the notable phases of the Upper Jurassic in central Europe 

 is the Solenhofen limestone of southern Germany. This stone is so 

 fine and so even grained, and at the same time so workable and so 

 strong, that it has come into use the world over for lithographic pur- 

 poses. It is also remarkable for the perfection of its fossils, including 



Fig. 356. — Sketch-map of Europe showing the relations of land and sea during the 

 later part of the Jurassic period. The shaded areas were submerged. (After 

 De Lapparent.) 



such delicate parts as the gauzy wings of insects. This limestone 

 has been ascribed to a late stage of the epoch, after the land to the 

 north had emerged. The newly emerged beds, largely limestone, were 

 still soft, so the hypothesis runs, 1 and the material washed down from 

 them gave origin, after deposition, to the lithographic stone. Others 

 have thought to see in the even grain of the stone a chemical precipi- 

 tate. Whatever the origin of the limestone, the perfection with which 



1 Neumavr, loc. cit., p. 318. 



