t^6 Account cfthe Peat Mojfes and Bhell Marl May 



this purpofe, with an iron auger fixed to its end. This makes 

 the operation of boring for marl both cheap and eafy. A pole 

 of twenty-five feet, he thinks, will, in general, be of fufficient 

 lengthy If the mofs be found to be deeper than this, it is eafy 

 to join another pole to the firll, or to obtain a new one of 

 a greater length. 



Shell marl iy found in the bottom of the generality of lakes, 

 and of meadows and mofTes which have once been lakes, through- 

 out Great Britain and Ireland. It is the remains "of myriads of 

 thofe forts of fmall teflaceous animals which commonly inhabit 

 pools of water, and have lived and died in thofe fituations. 



Some of thofe (hells are univalves, (generally Hetixy anitnal 

 Limaxy Lin.) others are bivalves, (generally Tellmay animal 

 Tethysy Lin.) and are frequently very entire when taken up; 

 but after a (hcrt expofure to the atmofphere, they crumble into 

 a fine whitifii powder which effervefces with acids, and is, in 

 hiCt, no way diirerent from powdered limeftone. It is com- 

 monly more pure from foreign and ufelefs ingredients than moll 

 iimeftones. Some mofs marl, examined by Dr Coventry, Pro- 

 fefTor of Agriculture at Edinburgh, v/as fouiul to contain Z^ per 

 cent, of pure chalk or carbonate of lime, which is more than 

 jime generally polTcffes, and the refufe of the marl was chiefly 

 peaty fubdance, which makes the refufe of fuch marl of more 

 ufe as a manurcj than that of limeftone, which is generally fand 

 or clay. 



Shell marl may be converted into quicklime by burning. Its 

 folution changes vegetable colours to green, and it pofleffes all 

 the other properties of quicklime, and, as fuch, is ufed for build- 

 ing in many places of England. 



De Pages, in his travels, mentions that the inhabitants of the 

 South Banks of the MiflirTippi make oyfter fhells ferve all thepur- 

 pofes of limeftone. And lands that receive manure from towns 

 where much lliell-filh is ufed, or that have (hells in their foil, 

 naturally, or by being brought to them from a (belly fea (horc, 

 (land in no need of lime for their culture, and are not at all 

 benefited by it. 



Some naturallfls, indeed, believe that all limeftones, marbles, 

 and other mafles of calcareous fubftances, are derived from the 

 remains of animals, and confolidaced either in confequence of 

 fufion by heat, or folution in water; and fome of ths fineft lime- 

 (tones and marbles ihow, unequivocally, that they are a congeries 

 of (hells of the ocean. Beds of thefe materials are frequently 

 found near the fummits of mountains, in which the (hells that 

 compofe them can be diftindly traced and enumerated by the 

 naturaliftr 



As 



