The geology of soils and substrata, with special reference to agriculture, estates, and sanitation . Photo by Prof. S. H. Reynolds.(i.) WEATHERED PORTLAND STONE, EAST OF ST. ALBANS HEAD, Photo by U. J. Harrison, (ii.) SURFACE-CREEP IN CAMBRIAN SLATES, NEAR ST. DAVIDS,PEMBROKESHIRE. QUATERNARY (RECENT AND PLEISTOCENE) 217 nelled in the direction of the slope, are strewn withangular blocks of quartzite, from 2 to 20 feet long. Be-neath the ground there is a flow of water. The move-ments have been explained as due to alternations of frostand thaw, the finer material being carried away by
The geology of soils and substrata, with special reference to agriculture, estates, and sanitation . Photo by Prof. S. H. Reynolds.(i.) WEATHERED PORTLAND STONE, EAST OF ST. ALBANS HEAD, Photo by U. J. Harrison, (ii.) SURFACE-CREEP IN CAMBRIAN SLATES, NEAR ST. DAVIDS,PEMBROKESHIRE. QUATERNARY (RECENT AND PLEISTOCENE) 217 nelled in the direction of the slope, are strewn withangular blocks of quartzite, from 2 to 20 feet long. Be-neath the ground there is a flow of water. The move-ments have been explained as due to alternations of frostand thaw, the finer material being carried away by stream-lets. This view is to a certain extent supported by Dr. ,* who remarks that the strata from which theblocks have been derived consist of bands of hard quartzite,separated by seams of soft and crumbling sandstone. Thesofter materials would be readily removed by streams, butthe hard and heavy blocks would remain, because theycould not be transported. The explanation might be applied to the scatteredgreywethers on the Wiltshire Downs, of which but a smallnumber remain of those that formerly were to be seen. Landslips. Landslips occur on steep slopes inland, and along manypar
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectgeology, bookyear1912
