Sandy calcareous marls may be examined by diffusing a few grains in water in a wine-glass, the lighter portions will be suspended in the fluid, and may be placed on glass, and when dry prepared with Canada balsam in the usual manner.
MICROSCOPICAL EXAMINATION OF FLINT.
Flint.—Flint, and other siliceous stones, require to be chipped into very thin fragments, and immersed in oil of turpentine. A clear, translucent flint should be selected, from which fragments may be shattered off by smart blows of a hammer, over a sheet of white paper: the most transparent flakes are to be selected, and these should be put in oil of turpentine, in a wide-mouth glass bottle. Take out the pieces for examination with forceps, and inspect them as transparent objects, by transmitted light. When good specimens are discovered, mount them in Canada balsam.
It is hazardous to entrust such fossils to the lapidaries; an interesting group of twenty spiniferites was reduced to ten, by one of our best workmen, in whose hands it was placed for polishing, with the view of rendering it more transparent.
[CHAPTER XI.]
FOSSIL TESTACEOUS MOLLUSCA, OR SHELLS.
