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FA ilM 1:RS' REi^^TK R, 



709 



Plate XVI.— /)ra."n:ge of quarries. 

 Fig. 1 ^- 2. 





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T 7a//of/Jn /-i.^^ 



JPzg. 2.— Section. S Spring oi outlet ol tbt water. 



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1^:V - ^ 



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Perliaps under this clay bed, there may be anotbw dry porous stratum into which the water may be let 

 down, and reduced to a stifl lower level; and this may b;- ascertained by boring an anger hole through the clay. 



through the bed of close stone in the quarry itself, 

 is the n:iosf advisable and least expensive method. 

 The situation ol" marl pits is commonly such. 

 that it reqnirs a very extensive cut ihrousrh some 

 part of the surrounding bank, to carry oH' the wa- 

 ter that prevents taking out the marl. This misrht 

 often be accom|)li.shed in a much less exjjensive 

 manner, by sinking a pit, or boring ihrough (he 

 retaining stratum under the marl bed, into some 

 absorbeni stratum below, that wou!d receive the 

 water let down into it by the pit or auger holes. If 

 the ground where the marl lies is oi" considerable 

 extent several pits or borings will be necessary to 

 carry off the water. If such pits require to be so 

 deep as to be in danger of closing up by the sides 

 falling in, they should be builr round the sides, or 

 filled up to near the top with loose stones, through 

 which the water can quickly and safrly subside. 

 Any cross drains, or cuts necessary tor collecting 

 the water, must be condiicted into the pits, in 

 many cases, the water may be got rid of in a still 

 easier manner, provided the situation of thecround 

 is favorable, [f the surrounding bank declines on 

 the opposite side lower than the water, by cutting 

 a drain into it, or boring \viih a horiznntnl auger. 

 into the tail (lowest termiiuilion) of the slraiian 



containing the water, it will be drav/n ott and re-^ 

 diiced to a level lower than that of the bed of 

 marl. As this water is often s(q)plied by a spring. 

 risin<r in some pan of ilie higher irround, and de- 

 scending into the place wiiere the marl lies, in 

 such case it will be necessary to cut off the soiu'ce 

 of this spring, and divert it inio some oiher chan- 

 nel. By douig tiiis. the quantiiy of water below 

 will be* lessened, and more easily carried oti by 

 means of the pits, dains, or auger holes. 



There are no pits of rock or clay marl in Scot- 

 land, like those in }^:n.'.^land ; but the same meth- 

 od ot" freeing them from water nn[)lies in all 

 similar cases."^ In niiiny parts of Etigland, much 

 2ood land is lost, by leaving these pits to remain 

 full of water, when they miiiht be so easily laid 

 dry by the nfeans thus described. 



"Springs (and consequently wetness) are some- 

 fitues found on the top of banks, and even hills, 

 1 where the ground immeditttely contiguous is low- 

 er on all sides ; but such sprmgs are sufiplied from 

 higher oTound at a distance, by means of water 

 conveyed ihrough the beds of porous freestone, in 

 the manner represented In' Plate No. XV'il. 



The coiiiituiatinn of th.e strata C D is supposed 

 ;o keep on the same rise, in the higher groui d on 



