On impressions of rain-drops in ancient and modern strata / Sir Charles Lyell.

  • Lyell, Charles, Sir, 1797-1875.
Date:
[1851]
Catalogue details

Licence: Public Domain Mark

Credit: On impressions of rain-drops in ancient and modern strata / Sir Charles Lyell. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    tends below it. In those impressions which have been made when the wind was blowing, and when the rain fell obliquely, the cavities are not only of an oval shape, hut all deeper at one end than at the other. Foot-prints of birds, and the winding tubular tracks of annelids are seen on the same surface with the rain-prints. On splitting open slabs formed by numerous thin layers deposited by successive tides, impressions of previous showers are seen, and casts of the same, standing out in relief on the under surface of incumbent layers. The Lecturer next considered the nature of certain small protube- rances, which might, on a cursory view, be mistaken for casts, which project from the upper surface of certain layers of mud, and are caused, some of them by dried bubbles of mud, and others by small particles of solid matter, covered with a film of mud. He also dis- tinguished between the cavities produced by air-bubbles rising up through the mud, which give rise to cavities differing in shape from those formed by rain, as he has proved by several experiments. In illustration of the foot-tracks of quadrupeds, such as the musk- rat, the mine, the dog and others, so common on the recent red sand of Kentville, on the borders of the Bay of Fundy in Nova Scotia, Sir C. Lyell exhibited a copy of a brick, one foot square from Babylon, now in the British Museum, on which the track of a small animal of the Ichneumon tribe, apparently the Asiatic Mongoose, is distinctly seen. This brick has been sun-dried (not baked in a kiln,) and must have been traversed by the creature, when the clay mixed with straw was still very soft. In the middle of the brick is an inscription in the Babylonian cuneiform character, which according to Colonel Raw- linson’s interpretation signifies that Nabokodrossor, King of Babylon, built certain cities, &c. This king is the same as the Nebuchad- nezzar of scripture, so that the brick is twenty-four centuries old. When the tidal waters densely charged with fine sediment creep gently over a slightly inclined sand or mud-bank, they do not disturb the surface, especially when it has been baked hard in the sun, as happens in summer in Nova Scotia ; and the new layer of matter which is thrown down, fills up all superficial indentations, which serving as moulds are protected from further disturbance by the casts thus taken from them. Mr. Cunningham threw out as a conjecture, that the fine-grained quartzose substance of Storeton Hill, might have resulted from blown sand. That such was really its origin. Sir C. Lyell, who has himself examined the quarries on the Mersey, entertains little doubt; for on the sea-shore near Savannah in Georgia, he saw the foot- tracks of raccoons and opossums which had been made in sandy mud at low water, in tbe course of being gradually filled up with blown sand, clouds of which were swept along by the wind from adjoining cliffs. This layer of sand when the tide rose again would in its turn be overspread by a new deposit of mud. After describing both the impressions and < asts of rain occurring in the recent red mud of the Bay of Fundy, the Lecturer pointed