andFosstl Remains near London. 349 



that the present account Is drawn up ahnost entirely from the pro- 

 ductions of chalk cliffs of not more than two miles in length, it will 

 not be difficult to conceive, that the number of these fossils is not less 

 in the English than in the French chalk. 



The state, in which these fossils are found, plainly evinces that the 

 matrix in which they are imbedded was formed by a gradual depo- 

 sition, which entombed these animals whilst living in their native 

 beds. The fine and delicate spinous projections of the shells are 

 unbroken, and the spines are still found adhering to the crustaceous 

 coverings of the echini -, neither of which circumstances could have 

 occurred had these bodies been suddenly and rudely overwhelmed by 

 these investing depositions, or had they been brought hither from 

 distant spots. 



It may be said that the specimens possessing the characters here 

 alluded to are rare. With respect to the spinous shells, however, 

 they certainly occur often, although it is almost impossible to extricate 

 them unbroken from their surrounding chalk ; and the rarity of the 

 specimens of echinites with their attached spines, depends in a great 

 measure on the mode in which these specimens are obtained. The 

 specimens seen in cabinets are seldom found by the naturalist him- 

 self, but are preserved by the work people who break the chalk, when 

 any uncommon appearances catch their eye. But it frequently hap- 

 pens that these marks are not seen until the piece is broken by their 

 tool, and with it, perhaps, the entire animal. 



The perfect state of the surfaces of the chalk fossils proves also 

 that this deposition proceeded from the surrounding fluid, and that 

 it was not derived fi-om the immediate action of any chemical agent ^ 

 on the shells and other calcareous coverings of the animals living at 

 the bottom of the sea. In the fossil animal bodies found in chalk, 

 not the least diminution of the sharpness of their ridges or points is 



