[' 527 ] 
ven or eight feet in depth, lies immediately above 
the fratum of fone, in which the bone was found. 
This fratum is never wrought by the workmen, 
being arenarious, and too foft for their ufe. It is 
about four or five feet thick, and forms a kind of 
roof to them, as they dig out the flone, of which 
the fates are formed ; for they work thefe pits in the 
fame manner as they do the coal-pits, leaving pillars 
at proper difances to keep their roof from falling in. 
This laf bed of f ate- ft one is about five feet depth, 
and lower than this they never dig. So that the whole 
depth of the pit amounts to about 24, or 25 feet. 
It was by working out the flate-fone, that this 
bone was difcovered flicking to the roof of the pit, 
where the men were purfuing their work ; and with 
a great deal of caution, and no lefs pains, they got 
it down inti re, but attached to a large piece of flone 5 
and in this fate it now remains in my pofiefilon. 
There is no water in the works, but fuch as de- 
fcends from the furface thro’ perpendicular fiffures ; 
and the whole is fpent in forming the fala&ites and 
f alagmites, of which there is great variety, and 
whofe dimenfions are confantly increafing. One of 
the workmen has been fo curious, as to mark the 
time of the growth of fome of them for feveral 
years paf . 
I am, with the greatef efeem, 
Dear Sir, 
Your ever obedient, 
and mof humble Servant, 
Jcflhua Platt. 
Oxon, 
Jan. 20. 1758, 
LXIX. 
