Petrefaffion found at Eaft Lothian «. 37 
fcance appeared to be fand, concreted and hardened into 
a kind of ftone. 
The fpeeknen now laid before the Society had been 
taken out of the fea, from the fame fpot, fome time be- 
fore,. and is a confolidated mafs that had undergone the 
fame change. It contains a piece of. rope that was ad- 
joining to fome iron ring, and. probably had. been tied 
thereto.. The fubftance of the rope is very little altered;, 
but the fand. is fo concreted round it, ; as to be as hard as, 
a bit of rock, and retains very perfectly impreffions of 
parts of the ring, juft in the fame manner as impreffions- 
of extraneous foflil. bodies are often, found in various, 
kinds of ftrata. 
Now, confidering thefe. circumftanees, we. may fairly 
conclude, in the firft place, that there is, on the coafts of 
this ifland, ^continual progreftive induration of mafles of. 
fand and other matter at the bottom of the ocean,, fome- 
what in the fame manner as there is at the bottom of the 
Adriatic fea, according to the. account given by Dr.. 
DON ATI 
And, in the next place (which is what more partial 
larly deferves our attention on this occalion), itlhould. 
feem, that iron, and the folutions of iron, contribute very 
much to haften and promote the.progrefs of the concre- 
tion and induration of ftone, whenever they meet and are, 
(a) Seethe Phil. Tranf. vd. XLIX. p, 588. 
united. 
