Mr. Limbird’s Account of the Strata, 6cc. jr 
a bed of dark-blue clay, which continues to the depth of 114 
feet from the furface, where there is a bed of Pone, of a 
brightifh colour, about 8 inches thick, and under it a bed of 
gravel, about 6 inches thick, where George Naylor fays 
there is another fait fpring. Under the gravel, there is abed of 
dark-coloured clay, refembling black-lead, which continues to 
the depth of 174 feet from the furface, when it changes to a 
chalky clay, intermixed with fmall pebbles and flints, which 
continues about 3 inches, and then changes to the fame kind 
of dark-coloured clay as before j in which, after boring to the 
depth of 186 feet from the furface, he came to the folid earth 
bored to, in 1747, by the above-mentioned Thomas Par- 
tridge. After boring in the fame kind of clay to the depth 
of 210 feet from the furface, it changes to a lighter-coloured 
one, which continues about 6 inches, and then changes dark 
again, and continues fo to the depth of 342 feet from the 
furface, where there is a bed of fhells and white-coloured 
earth, about half an inch thick, and under it a light-coloured 
earth like that at 210 feet from the furface* and under it a 
bed of dark-coloured clay. After continuing in that clay to 
the depth of 444 flpet from the furface, George Naylor 
put down a tin pipe, 50 yards in length, and 2 1 inches in 
diameter within, to prevent the gravel and Pones from falling 
down and obflrufting the rods; but being too w 7 eak for that 
purpofe, it feparated into different lengths, and intirely pre- 
vented his boring, fo that he was* obliged to get the faid 
pipes up again, which took him 48 days ; having got them up, 
and cleared the hole pretty well, he left off boring until he 
could procure fome Pronger pipes. 
In July, 17S4, he put down 21 pipes of cafl iron, which 
were caff at Cheffer field, in the county of Derby, each pipe 
H 2 being 
