W. A. Richardson — The Origin of Cretaceous Flint. 545 



TABLE No. 1. 



5. Summary. 



1. An examination of the amounts of silica disseminated through 

 the Chalk and segregated as flint reveals a distinct and striking 

 inverse relation between them. 



2. The amount of silica present as flint is found to be of the same 

 order as that disseminated, and confirms the conclusions at which 

 Professor Sollas has already arrived. The silica, that is, might 

 easily have been derived from the remains of siliceous organisms 

 buried in the Chalk, and only requires a moderate thickness for the 

 supply. 



3. The rhythm found in the recurrence of flint lines presents 

 a striking similarity to the Liesegang banding ; and in general a study 

 of flint distribution strongly supports the hypothesis that the flint 

 originated by the rhythmic precipitation of solutions diffusing through 

 the Chalk at the time of uplift. 



Whether these conclusions apply to flint-like segregations in other 

 formations it is impossible to say, since there is no such body of 

 quantitative data available for their study as exists for that of the 



DECADE VI. — VOL. VI. — NO. XII. 35 



