Arm Chair in the Louvre Collection.
VI. GEOLOGY.--The Deposition of Ores.--By J.S. NEWBERRY.--Mineral
Veins.--Bedded veins.--Theories of ore deposit.--Leaching
of igneous rocks.
VII. NATURAL HISTORY, ETC.--Habits of Burrowing Crayfishes
in the U.S.--Form and size of the burrows and mounds.--Obtaining
food.--Other species of crayfish.--3 figures.
Our Servants, the Microbes.--What is a microbe?--Multiplication.
--Formation of spores.--How they live.--Different groups
of bacteria.--Their services.