402 ON THE FORMATION OF THE CHALK STRATA, 



ceeds from the mouth of the fossil echinite found in chalk, as 

 if the animal matter which had flowed from that orifice had 

 been petrified and changed into silex. He hazards no opinion 

 of his own. Traite, vol. i. p. 316. 1807. 



The recent work of Daubuisson, which is one of the most 

 elaborate and extensive that has been published for some 

 years, goes a little deeper into this subject. Talking of the sphe- 

 rical masses of flint, § 119. found in the limestone of Bavaria, 

 he observes, " that they very probably owe their origin to a re- 

 union of siliceous particles, which were disseminated in the 

 calcareous mass still soft or fluid ; yielding to their attractive 

 force, they had grouped themselves, and, as it were, formed 

 themselves into balls, round a centre. If this arrangement 

 had not been accomplished in so perfect a manner, or that the 

 attractions had operated in several, or around different neigh- 

 bouring centres, tuberose masses would have been the re- 

 sult, and not balls ; such is probably the origin of the flints 

 which occur in such abundance in the chalk and other calca- 

 reous beds." 



Having thus described the mode of formation of flint, he 

 adds, § 301. " that the particles of carbonate of lime, which have 

 formed the secondary limestone, appear to have been frequent- 

 ly mixed, in the fluid from which they were precipitated, with 

 particles of silex, which were deposited at the same time. If 

 these had been in small quantity, and had rested disseminated 

 in the mass, limestone, impregnated with silex, would have 

 been the result, and if they had united, a few detached flints 

 would have been produced ; but if they had been abundant, 

 either the Silici-calce of Saussure would have been formed, 

 or a great number of tuberose flints. I have sometimes seen 

 them so abundant, that they touched, and the limestone only 

 filled the interstices. At some moments, and in some points, 



the 



