SILICIFIED CORALS, FLINTS, LIMONITE
Mode of occurrence of the silicified corals, 351.—Their character and
structure, 352.—Flints, nodules of Chalcedony, Agates, etc.,
353.—Other siliceous concretions, 354.—Jasper, 355.—Deposits of
Limonite, 356.—Magnetic Iron-sand, 357.—Suggested explanation of the
silicification of the corals, 358.—Note on a silicified Tree-fern, 360
_Pages_ 350-360