^r. 



I 



2. 





i 



"'' "^ JiV4j 



^vater 





can de. 



of 



^vhich 



and 



are 



'^ waters fi 

 the ri 



roiti 



rivers i 



m 



_^ P''cviouflj 

 '"'■ed to (hew, 

 ?H as the 



e 



primeval 



uaiuityoffea. 

 the fifli 



ures 111 



!::uic produc- 

 craters of vol- 



tains, lie f^'iN 



jrnalllrataiiot 



up 



1 



the fe 



lereexpc^edto 



i^ra very 



bluiit 



/ 



railed with ^^^ 

 ; if at the on- 



{i)oS 



) 



{Iratum 



ooiin 



taiii 



;„ beii'g 



er: 



On 



d,th^ 



.fs u'^ 



ae\\'5 



alt 



der 





Sect. XI. i. 3 



AND WATERING. 



259 



hill : and either form a morafs below 



weep 



k by 



places ; or many of thefe lefs currents meetm 



& 



ther burft out in a more cop 

 The immediate caufe of fpr 



fifts therefore in the cond 



fation of the atmofph 



moifture, during th 



principally, by 



t 



he -reater coldnefs of the fummits of hills, which is explained in d 



the Botanic Garden, Vol. I. additional note 26 



The water 



den fed 



the fummits of 



defcends between the ftrata 



of the incumbent foil, fometlmes for many miles together; but ge- 

 nerally from the neareft eminences into the adjoining vallles. 



3. Thus there Is a flratum of marl, which 1 have obferved on the 

 furface of the lands about Derbv, which extends many miles in moft 



diredlon 



This flratum of marl is of 



thlcknefs from 10 to 



50 feet, and beneath it lies a ftratum of fand, which is alfo of 



thlcknefs from a few inches to fix or eight feet. 



dof 



degrees of ind 



d beneath 



ther flratum of mar 



nknown depth. On the top of Radborne common, about fi 

 miles north-weft from Derby, the fandy ftratum is quite loofe 



d 



ri 



fes above the ftrat 



of marl, which is deficient at the fummlt of 



the hill. Three or four ftrong fprings of water burft out on the fides 

 of this hill, which thus originate from the moifture of the atmo- 



fphere cond 



fed 



the cold fummlt, and pafllng through the fandy 



ftratum between the two ftrata of marl. 



In the road to Duffield, about two miles north of Derby, th 



fand-ftratum is cemented 



fton 



as 



Radborne-common above mentioned 



Th 



I fome fituation 

 ftratum of fand 



ftone is fome feet in thlcknefs, and lies four or five yards deep, be 



eath the u 



ppe 



ftratum of 



marl, dividing it from the lower one. 



imagine it 



At Normanton, about two miles fouth from Derby, the fand-ftra 

 turn confifts. of a loofe fand, fo white and pure, that I 

 might be ufed in the manufadure of flint-glafs, and lies about twelve 

 feet deep, beneath the upper ftratum of marl, dividing it from the 



LI2 



under 



