3. “Dr. Hitchcock.” (1793-1864.) An American geologist and author. 4. “Minute animals.” The carbonate of lime which is found in rocks is most of it formed directly of shells, corals, and other animal remains. These little creatures take their stony-like structures from the water or from their food through the power of secretion, just as man forms his bones, and after their death they are given over to be made into rocks. The great extent and thickness of the limestone rocks of the earth give some idea of the amount of life that flourished there in past time. 5. “Anhydride.” For definition see “Chemistry,” page 151. 6. “Old Stone Mill.” It is asserted by some antiquaries that this structure was built by the Northmen, 500 years before Columbus landed on these shores. Its purpose, as well as its origin, has been a theme of much discussion. Its present appearance is that of a large round tower overgrown with vines. 7. “The Stone age.” One of the divisions of prehistoric time. In this age men were not acquainted with the use of metal and fashioned their rude implements exclusively out of stone. 8. “Ceramic,” se-ramˈic. 9. “Cesnola collection.” Cesnola was an American soldier and archæological explorer, born in Italy in 1832. He served in the Crimean war, and in the civil war, was for a long time in Libby Prison. At the close of the war he was sent as consul to Cyprus. Having his attention attracted by some fragments of terra cotta and some coins, he began making excavations in search of relics. He met with such rewards that he continued his work for three years, employing hundreds of men. Among his discoveries were statues, lamps, vases, coins, glassware, gold ornaments, bronzes, and inscriptions, in all about 13,000 articles. This remarkable collection is now in the Metropolitan Museum of Art in New York. 10. “The mound builders.” The race of people found in America by its first settlers had clearly been preceded by a race of higher type and attainments. Relics proving this have been discovered throughout the Mississippi valley. Earthworks are their principal testimony, of which many thousands have been found in Ohio alone. These mounds vary in size and shape, but are always regularly formed, sometimes being square, sometimes round, hexagonal, octagonal, or truncated. They are ascended by spiral paths, and frequently contain skeletons. Sometimes the earthworks are thrown up so as to represent in outline men and animals, and appear as huge “bas-reliefs on the surface of the ground.”