Narrative of the surveying voyages of his majesty's ships Adventure and Beagle (vol.2): between the years 1826 and 1836 : describing their examination of the southern shores of South America, and the Beagles's circumnavigation of the globe

678 A ¥Kvr REMAUKS over, and landed among other recent compositions. In what other way could such a mass of these animalcules be heaped together ? There are also effects of existing causes which authors have only mentioned by name, in reference to the Deluge, with- out explaining that the effects alluded to would have been enormously increased at that time ; — I mean the tides. — In the Appendix to this volume is a short statement of the man- ner in which tides may act — upon the principles of the ocean oscillating in its bed ; and of tides being caused, partly by the water being elevated by the moon and sun, partly by a westward momentum given to it by their attraction, and partly by the oscillation caused by the return of the fluid after being elevated. If this globe were covered with water to the height of a few miles above the present level of the ocean, three more particular effects would take place : an enormous pressure upon the previously existing ocean, and on all low land ; a dimi- nished gravity in the uppermost waters, resulting from their removal from the earth's centre ; and immense tides, in conse- quence of the increased depth of the mass, the diminished weight of the upper fluid, and the augmentation of the moon's attraction. As the waters increased on the earth, the tides would also increase, and vast waves would rush against the sides of the mountains, stripping off all lighter covering, and blowing up,* or tearing down, enormous masses of rock. Similar effects would take place as the diluvial ocean decreased, until it became bounded by its proper limits. Such oscillations I conceive to be alluded to by the words " going and return- ing,'"! a^nd ^y the expression, " they go up by the mountains ; they go down by the valleys C^ which exactly describes the rushing of enormous waves against high land. When a wave strikes against a rock, it dashes up every projection that opposes it ; but — its impetus at an end — down the water runs • By the extraordinary power, or principle, called the hydrostatic paradox. f Gen. viii., V. 5, marginal translation. I Psalm civ. ver. 8.