On the Danger of Hasty Generalization in Geology. 431 
carboniferous fossils in the primitive limestone. Fortunately 
for truth, a friend obtained many similar specimens in the 
establishment of a marble-cutter in Leith Walk, where I 
soon found the true explanation of the structure which had 
led me to maintain its organic origin. 
It is usual for the marble-cutters at Carrara, before send- 
ing out the blocks from the quarry, to reduce them into as 
small dimensions as possible. This operation is performed by 
what is called a matting-hammer, consisting of many separate 
and blunt teeth placed alternate to each other, and is used by 
bringing the hammer down, in a perpendicular direction, to 
the flat face of the marble block. By this method a series of 
quinquncial indentations are produced precisely similar to 
those found in Stigmaria, and, to render the illusion more per- 
fect, where the percussion of the teeth of the hammer is 
greatest (which is at the point), the limestone at the bottom of 
each depression is more crushed, and being deprived of its air 
by the greater force, exhibits a different structure from the 
surrounding walls, and thus presents the regularity, both in 
shape and direction, of the protruding petioles of Stigmaria. 
Unfortunately, before this discovery was made, my dear 
friend Professor Fleming died, and I have no doubt that this 
specimen is now lying in his cabinet, labelled on my authority 
as a Stigmaria. Another instance of the danger of hasty 
generalization which occurred to myself — the supposed native 
lead of Inch Mickery — was formerly brought before this So- 
ciety, and is published in our Proceedings, vol. ii. p. 85. 
I have now to deal with another instance in which a hasty 
generalization has met with more attention in the geological 
world than any of those I have mentioned, but not less than 
it deserved. Mr Geikie, in a paper published in the " Edin- 
burgh Philosophical Journal," vol. xvi. p. 102, has stated his 
belief that the ground on which Leith is situated has risen to 
the extent of 25 feet since the Roman period. The section 
from which he has come to this conclusion is in a sand-pit at the 
Junction Road, Leith, and is represented in the diagram, which 
is the same as Mr Geikie used to illustrate his paper. He thus 
describes the succession of the strata as seen in the sand-pit 
" The lowest bed (1) visible is one of coarse gravel or 
VOL. II. 3 Iv 
