 ... thus building up their channels and obstructing the outlets of the tunnels. The blocking of the tunnels must cause the subglacial streams to lose force and deposit sand and gravel on the bottom of their channels ; this causes the water to flow at...  Ice-work, Present and Past - Página 75por Thomas George Bonney - 1896 - 295 páginasVista completa - Acerca de este libro
 | 1893 - 988 páginas
...their channels ; this causes the water to flow at higher levels, and coming in contact with the roofs of the tunnels, enlarges them upwards ; this in turn...periodic variations in the volume of the streams, may be formed within the ice. When the glacier melts, the gravel ridges contained within it will be... | |
 | Geological Survey (U.S.) - 1893 - 746 páginas
...their channels; this censes the water to flow at higher levels, and coming in contact with the roofs of the tunnels, enlarges them upwards; this in turn...When the glacier melts the gravel ridges contained within it will be exposed at the surface, and as the supporting walls melt away, the gravel at the... | |
 | 1893 - 912 páginas
...their channels ; this causes the water to flow at higher levels, and coming in contact with the roofs of the tunnels, enlarges them upwards ; this in turn...periodic variations in the volume of the streams, may be formed within the ice. When the glacier melts, the gravel ridges contained within it will be... | |
 | Israel Cook Russell - 1897 - 280 páginas
...their channels ; this causes the water to flow at higher levels, and, coming in contact with the roofs of the tunnels, enlarges them upwards ; this in turn...periodic variations in the volume of the streams, may be formed within the ice. When the glacier melts, the gravel ridges contained within it will be... | |
 | Israel Cook Russell - 1904 - 304 páginas
...their channels ; this causes the water to flow at higher levels, and, coming in contact with the roofs of the tunnels, enlarges them upwards ; this in turn...grow in height. In this way narrow ridges of gravel arid sand, having, perhaps, some stratification due to periodic variations in the volume of the streams,... | |
 | 1893 - 910 páginas
...their channels ; this causes the water to flow at higher levels, and coming in contact with the roofs of the tunnels, enlarges them upwards ; this in turn...periodic variations in the volume of the streams, may be formed within the ice. When the glacier melts, the gravel ridges contained within it will be... | |
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