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Show xii CONTENTS. PAGE CHAPTER XVIII. Formation of coral reefs-They are composed of shells as well as coralsConversion of o. submerged reef into an island-Extent and thickness of coral formations-The Mo.ldiva isles-Growth of coral not rapid-Its geological imJJOrtance-Circular and oval forms of coral islands-Shape of their lagoons -Causes of their peculiar configuration-Openings into the lagoons-Why the windward side both in islands and submerged reefs is higher than the leeward-Stratification of coral formations-Extent of some reefs in the Pacific-That the subsidence by earthquakes in the Pacific exceeds the ele· vation due to the same cause-Elizabeth, or Henderson's Island-Coral and shell limestones now in progress, exceed in area any known group of ancient rocks-The theory that all limestone is of animal origia, considered-The hypothesis that the quantity of calcareous matter has been and is still on the increase, controverted • 283 • ERRATA. Frontispiece, for Montagnolo. read Montagnuola. Page 39, line 2 from the bottom, for excusively read exclusively. 131 - 14 - top - Hypnum - Sphagnum, 147 - 21 top, dele of. 178 - 8 top, jo1· even read ever. 4 ..... |