MODE IX. GYPSUM. 497 



sand at Grignon, about four leagues beyond 

 Versailles, have also been discovered in the gyp- 

 sum of Montmartre. Most of the shells found 

 at Grignon, some of which retain their most de- 

 licate spines, and even their colours, are known 

 now to belong to the South Sea, a portion of the 

 Grand Ocean falsely called the Pacific; and 

 but few to the Atlantic, or even the Mediter- 

 ranean. 



The various beautiful kinds of selenite, or 

 crystallised gypsum, found at Montmartre, be- 

 long to lithology. The curious kind called ve- 

 getable selenite, from its resemblance to vegeta- 

 tion, seems confined to Derbyshire. 







Aspect 1. Common gypsum, from Montmartre. 



The same, with selenite, often elegantly inter- 

 spersed with farinaceous gypsum. 



The same, with blue variegated clay. 



The same, in small layers of marl, &c. forming, 

 as it were, a Montmartre in miniature. 



The same, with imbedded ossilites, or bones of 

 quadrupeds and birds. 



The same, with various sea-shells ; a recent and 

 curious discovery. Brongniart says that some of 

 the marl beds contain cardites, venerites or dion- 

 ites, tellenites, cerites or screws (turbinites), and 



VOL. i. 2 K* 



