59 o SCIENCE PROGRESS 



scarcely have united to almost solid blocks, unless the activity 

 had been prolonged over a considerable period and involved 

 rather wide areas. They could scarcely have been laid down 

 without occasioning a considerable rise of temperature locally, 

 and probably not without the formation of large quantities 

 of carbon dioxide. Both of these would have contributed to 

 increase the water-vapour content of the atmosphere with still 

 further rise of temperature, vast cloud-formation, prolonged 

 and violent precipitation, and accompanying electrical activity. 

 Indeed, it seems not improbable that the implied conditions 

 would in some degree approach, locally at least, the conditions 

 imagined in the formation of a solid crust over a molten earth. 

 It is possible that the different surface conditions conceivable 

 under the nebular and the various meteoritic hypotheses would 

 be differences of degree and generality rather than of kind, 

 and that for our present purpose it matters little whether we 

 accept one or the other, or regard them all as unsubstantiable 

 at present. 



There seems no more reason why such outbreaks should 

 have taken place in Cretaceous than in Archean time. Neither 

 does there seem any particular foundation for the long prevalent 

 idea that the earth in the Archean period was entirely covered 

 by water. The apparent fixity of the continental areas through 

 known periods of enormous duration would itself suggest that 

 there had been, even in the remotest ages, the recurrent pro- 

 jection of volcanic areas above the level of the sea. Possibly 

 we have in the recent eruptions in the Bogaslov Islands a dim 

 suggestion of primeval conditions; 1 and the anciently volcanic 

 area in Yellowstone Park known as Hell's Half-Acre, with its 

 boiling springs, its geysers, its gas-vents, and the varied 

 mineralisation of its waters, may offer us a faint picture of an 

 ancient day when a similar area, perhaps of much greater 

 extent, was thrust up out ol the Archean ocean. 



1 According to officers of the revenue cutter McCulloch, which returned from 

 a cruise in northern waters, Mount McCulloch, which last year thrust its head up 

 from the centre of Bogaslov Island, sixty miles west of Unalaska, has disappeared 

 in the throes of another volcanic change. In its place, it is said, is a land-locked 

 bay three miles wide, into which the cutter Busk sailed and made soundings. 

 It was found that the water showed a depth of from eight fathoms at the edge 

 to twenty-five fathoms in the centre. Mount McCulloch, which was first seen a 

 year ago, when the cutter after which it is named arrived off the coast, had a 

 height of 300 ft.— San Francisco dispatch, November 6, 1908. 



