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Remarhs on a Deposit of Shell-Marl. By Mr James Mitchell, Surgeon, 



Eoyal Navy. 



About a mile and a half from Wooler, Northumberland, on the 

 estate of Colonel Hughes, called Middleton Hall, there is a very ex- 

 tensive deposit of shell-marl, about three or four acres in length, and 

 one in breadth. The Colonel remembers it as a lake, with its margin 

 and banks adorned with trees and shrubs ; it seems to have been fed 

 by numerous springs, some of which exist even in the present day ; 

 but it has been so well drained that now it may be crossed anywhere 

 in safety, and is indeed so dry as annually to yield a fine crop of 

 natural hay. Only a very small part of this agricultural treasure has 

 been dug into, no more being taken out than suffices for the use of the 

 estate, and it has produced very luxuriant crops. Yet, small as is the 

 part which has been opened, there is sufficient to interest the observer 

 of nature. Previous to its being drained, the peat was so spongy as 

 to measure about four feet deep ; it is now reduced to between two 

 and three. In this peat, which covers the marl, were found oak and 

 willow trees, with acorns, hazel-nuts, &c. ; but no remains of animals 

 have yet occurred in it. The marl, so far as they have yet dug, is, in 

 the best places, about ten feet, but it varies in thickness, and it is very 

 likely that it will be thicker in the centre. It is white, with rather a 

 yellow tint. In its upper strata the shells are very perfect, but below, 

 from the greater pressure, they are broken or comminuted, and in 

 general obliterated. They are the same species which are found in 

 fresh-water ponds at the present day ; and, through the kindness of 

 Mr Nichol of Edinburgh I am enabled to give their names, viz., Cyclas 

 cornea, C. pusilla, Succinea amphibia, Planorbis contortus, PI. fontanus, 

 Limneus pereger, Valvata obtusa, and V. spirorbis. There were found 

 also in the marl two complete skeletons of the red deer (Cervus elephas), 

 with very large branching antlers. They were standing in an upright 

 position, which seems to corroborate the statement of Mr Lyell, who 

 says — " Deer, and such species as take readily to the water, may often 

 have been mired in trying to land where the bottom was soft and 

 quaggy, and, in their efforts to escape, may have plunged deeper into 

 the marly bottom. Some individuals, we suspect, of different species, 

 have fallen in when crossing the frozen surface in winter, for nothing 

 can be more treacherous than the ice when covered with snow, in con- 

 sequence of the springs which are numerous, and which, always 

 retaining an equal temperature, cause the ice, in certain spots, to be 

 extremely thin, while, in every other part of the lake, it is strong 

 enough to bear the heaviest weights." — Prin. of Geol. vol. ii. p. 251. 



