766 APPENDIX. 



or when slightly submerged.— 666. Effects if the surface of a continent is nearly 

 level, there being no mountains.— 667. Nature of Glaciers.— 670. General cha- 

 racters and movement. — 671. Circumstances influencing their formation. — 672. 

 Law, and rate of flow. — 673. The three principles on which the power of motion 

 depends. — 674. Cause of the laminated structure of a glacier. — 675. Method of 

 transportation, and the materials transported. — 676. Kinds and methods of ero- 

 sion. — 677. Origin and effects of Icebergs. — 678. Methods by which sedimentary 

 strata have been formed. — 679. Extent of erosion over continents. — 680. De- 

 pendence of topographic effects on the characteristics of the rocks of a country. 



XXVI. Heat.— Page 681. Three sources of heat.— 682. Effects of the sun.— 

 Id. of chemical and mechanical action. — Effects over the globe of internal heat. 

 — Proofs of the existence of internal heat. — 683. Rate of increase with the 

 depth. — Evidence of internal heat from volcanoes. — 684. Probable thickness of 

 the earth's crust. — 685. A volcano; lava; cinders; crater. — Ejections; tufa. — 

 General geographical distribution of volcanoes, and where few. — 6S7. Material 

 of a volcanic mountain ; lava-cones. — 689. Tufa-cones. — Cinder-cones. — 690. 

 Mixed cones. — Lava; scoria. — 691. Liquidity of lava; effects of superheated 

 steam. — Vapors or gases. — 692. Effects of vapors. — 693. Movements. — 694, 695. 

 — Causes of eruptions. — 697. Eruptions mostly through fissures, and results. — 

 698. Origin of forms of volcanic cones. — 700. Geysers. — Source of volcanoes. — 

 702. Formation of dikes. — 704. Metamorphism. — Effects. — 705. Changes by loss 

 of water, or other vaporizable ingredient. — 706. Obliteration of fossils, and 

 crystallization. — 707. Origin of metamorphic changes; amount of heat required. 

 — 708. Effects from the water present. — 710. Conditions attending metamor- 

 phism. — 711. Veins. — 712. Three methods of filling veins. — The method by 

 which the larger part of veins have been formed, and evidence of filling by suc- 

 cessive supplies of material. — 713. Sources of material, and how carried into 

 open spaces. — 714. Alterations of veins. — 715. Faulted veins. 



XXVII. Movements in the Earth's Crust, and their Consequences. — 

 Page 716. The four subjects here included. — Causes of local change of position 

 or level. — 717. Action of vapors; of gravity of deposits; of internal tides. — 



718. Effects from change of temperature in the earth's crust, and examples. — 



719. Consequences from inequalities in the crust. — Effects how long in progress. 

 — Direction of the force, and positions of the axes of resulting plications. — 719. 

 Example in the Appalachians (see pp. 403-407). — 721. Flexibility of rocks, and 

 evidence. — 722. Formation of synclinal valleys. — Elevation of mountains. — 

 Proof that the epochs of elevation occurred only at long intervals. — 723. Effects 

 during the intervening time. — On what the water-level depends. — 724. Courses 

 of elevations may be the same in different periods, different in different periods, 

 different in the same period. — 725. First five causes of fractures mentioned. — 

 726. The sixth cause. — The seventh, and its mode of action. — Direction of frac- 

 tures. — 727. Causes of faults, and mode of formation. — Mode of production of 

 slaty cleavage. — 728. Id. of joints in rooks. — Characteristics of an earthquake. 

 — The two kinds. — 729. Effects. — Earthquake oceanic waves. — 730. Cause of 

 earthquakes. — 731. First, second, third, fourth, and fifth principles mentioned as 

 to the system in the earth's features. — The sixth. — 732. The seventh. — The eighth 

 and ninth. — The tenth. — Deductions as to the direction, position, and mode of 

 action of the force originating these features or peculiarities of the earth. — 734. 



