The direct petrographical suggestion is that they are chemical precipitates. If now we accept this hypothesis, it becomes apparent that there are three possible sources for the silica so precipitated, viz.: (1) Siliceous springs in the bottom of the ocean,... The Philippine Journal of Science - Seite 1671907Vollansicht - Über dieses Buch
| Elmer Fred Davis - 1919 - 832 Seiten
...silica cannot be proved to be the extremely altered dfibris of Radiolaria. The direct petrographical suggestion is that they are chemical precipitates....the bottom of the ocean, similar to those well known iu volcanic regions; (2) radiolarian and other siliceous remains, which may have become entirely dissolved... | |
| 1897 - 910 Seiten
...description of the jaspers several theories of their origin are considered. The theories are as follows : (i) siliceous springs in the bottom of the ocean, similar...other siliceous remains which may have become entirely disssolved in sea water; (3) volcanic ejcctamenta which may have become similarly dissolved. The two... | |
| Elmer Fred Davis - 1915 - 266 Seiten
...silica cannot be proved to be the extremely altered d6bris of Badiolaria. The direct petrographical suggestion is that they are chemical precipitates....entirely dissolved in sea water; and (3) volcanic ejectmenta, which may have become similarly dissolved. The last is the least probable, because we are... | |
| University of California, Berkeley. Department of Geology - 1919 - 712 Seiten
...silica cannot be proved to be the extremely altered dfibris of Badiolaria. The direct petrographical suggestion is that they are chemical precipitates....entirely dissolved in sea water; and (3) volcanic ejectmenta, which may have become similarly dissolved. The last is the least probable, because we are... | |
| University of California (1868-1952) - 1918 - 702 Seiten
...silica cannot be proved to be the extremely altered debris of Radiolaria. The direct petrographical suggestion is that they are chemical precipitates....entirely dissolved in sea water; and (3) volcanic ejectmenta, which may have become similarly dissolved. The last is the least probable, because we are... | |
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