74 MICROSCOPICAL OBJECTS FOUND 



from being loaded with an oxide of iron, presents 

 identical organisms. They also exist still lower 

 down, in the Grey Chalk, which passes into the 

 blue clays of Speeton. 



William Harris, Esq. of Charing in Kent, and 

 Dr. Mantell, have submitted to my inspection 

 specimens of a deposit of chalky marl, which was 

 discovered by Mr. Harris, at the foot of the 

 Chalk hills, at Charing. The deposit, resting 

 upon the upper Green-sand is about a foot thick, 

 chiefly consisting of soft white tenacious clay ; 

 but contains vast numbers of the beautiful Fora- 

 minifera, and other organisms characteristic of 

 the Chalk, and which Mr. Harris has distributed 

 with the utmost liberality amongst those who are 

 interested in the subject. Its origin appears to 

 be somewhat obscure, but, as Mr. Harris suggests, 

 the most probable explanation is, that it was formed 

 at the time the Chalk hills obtained their present 

 undulated contour, and that the deposit in question 

 was some of the resulting debris. Plate 4, is 

 devoted to some of the very beautiful organisms 

 which the clay contains. They are easily sepa- 

 rated by washing, and become as clean and 

 perfect as they could be, even in the most recent 

 deposits. 



