The Geology of Sidmouth and of South-eastern Devon

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J. Harvey, 1843 - Devon (England) - 69 pages
 

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Page 49 - ... in general beautifully preserved in the chalk ; substances of no greater solidity than common sponges retain their forms, delicate shells remain unbroken, fish even are frequently not flattened, and altogether we have appearances which justify us in concluding that, since these organic exuviae were entombed they have been protected from the effects of pressure by the consolidation of the rock around them, and that they have been very tranquilly enveloped in exceedingly fine matter, such as we...
Page 48 - Organic remains are in general beautifully preserved in the chalk ; substances of no greater solidity than common sponges retain their forms, delicate shells remain unbroken, fish even are frequently not flattened, and altogether we have appearances which justify us in concluding that, since these organic exuviae were entombed they have been protected from the effects...
Page 36 - Luc, and one which is still proceeding at a considerable rate, the fall of the cliffs being frequent, particularly in bad weather. Much loss of coast is sustained near Sidmouth, particularly in the direction of High Peake, the small green-sand cap on the top of which will disappear at no distant date, geologically speaking, and be only known to have existed from the geological maps now constructed of that part of the country.
Page 57 - ... varieties of colour. In the Greensand the Chalcedony is often extremely beautiful, and pieces sufficiently large to form small cups or vases, might be sometimes obtained. Portions of this mineral when worked into seals cannot be distinguished FLOATSTONE.
Page 29 - ... every rain over the district there is a general movement of the particles composing a large portion of its surface from their previous places to lower levels. The amount moved may be comparatively insignificant during a year or a century, but the cubic contents of that which descends to lower ground, during the lapse of a great geological period, must be very considerable. (De la Beche, 1839, p.
Page 29 - ... and a large part of West Somerset, the descent of this detritus can be seen to be taking place in all directions, more particularly during heavy rains. According to the quantity of water, slope of ground, and other necessary conditions, will it be seen to travel. During every rain over the district there is a general movement of the particles composing a large portion of its surface from their previous places to lower levels. The amount moved may be comparatively insignificant during a year or...
Page 55 - ... particles of green silicate of iron. When first quarried this stone is, as is generally the case with similar materials, somewhat soft and easily worked, from the presence of the water disseminated through the stone, becoming hard when this water has been evaporated by exposure. The chief quarry is subterraneous, and extends into the hill about 180 yards, the roof being supported by large square pillars formed by portions of the workable beds left standing.
Page 55 - The roof is sustained by large square pillars formed by portions of the workable beds left standing. particles of green silicate of iron. When first quarried this stone is somewhat soft, and is easily worked, but it rapidly hardens on exposure.
Page 29 - ... more particularly during heavy rains. According to the quantity of water, slope of ground, and other necessary conditions, will it be seen to travel. During every rain over the district there is a general movement of the particles composing a large portion of its surface from their previous places to lower levels. The amount moved may be comparatively insignificant during a year or a century, but the cubic contents of that which descends to lower ground, during the lapse of a great geological...
Page 8 - Beche, when speaking of this formation, "such as the rothliegendes,* the lowest member of the red sandstone group, over a considerable area, often remarkable for containing fragments of pre-existing rocks of such size as to constitute a conglomerate, is certainly exceedingly striking, particularly when it is observed that fragments of porpheries are abundant in many places.

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