CHAPTER IV.
CONSOLIDATION OF STRATA AND PETRIFACTION OF FOSSILS.
Chemical and mechanical deposits--Cementing together of particles--Hardening by exposure to air--Concretionary nodules--Consolidating effects of pressure--Mineralization of organic remains--Impressions and casts how formed--Fossil wood--Goeppert's experiments--Precipitation of stony matter most rapid where putrefaction is going on--Source of lime in solution--Silex derived from decomposition of felspar--Proofs of the lapidification of some fossils soon after burial, of others when much decayed 33