17. Sulphuret of Silver. With sulphuret of lead. Same locality.
18. Tourmalin. In masses of crystalline quartz. Rhinebeck.
Very respectfully,
F. C. SCHAEFFER.
The following notices were prepared before the receipt of the above letter.
Other Localities of Minerals and of ANIMAL REMAINS, and acknowledgments of Specimens received.
Guadeloupe.—Native sulphur, obsidian, pitchstone, native alum, basaltic hornblende, alum covered with sulphur.
Porto Rico.—Hexagonal crystals of mica.
Specimens of the above minerals are in the cabinet of Mr. John P. Brace, at Litchfield, Connecticut.