of Edinburgh, Session 1877 - 78 . 
695 
“ Iron, . . 44 ‘5 6 per cent. 
“Sulphur,. . .52-14 „ 
“ Coaly matter, . . 3*30 ,, 
Deducting the coaly matter, the iron and sulphur would he in the 
proportions in which they are generally found in ‘marcasite,’ viz., 
“ Iron, 45*61; and Sulphur, 54 •29.” 
As regards chemical compositions, therefore, the small metallic 
boulder may be considered as exactly agreeing with the nodules 
found in the Campsie coal strata. This agreement in composition 
affords a strong ground for inferring that the boulder had been 
transported from Campsie, or from Kilsyth, as suggested by Mr 
Peach. 
With regard to the larger spherical ball found in the same bed of 
boulder clay at Leith, I am now able also to indicate the part of the 
country from which it was probably transported. Mr Hutchison 
of Carlo wrie, happening to see this stone ball, informed me of two 
quarries in Linlithgowshire where concretions resembling it were 
in abundance. These quarries are near Humbie and Dalmeny, 
situated from nine to ten miles due west from Edinburgh. Mr 
Hutchison having sent to me several of these concretions, I was 
induced to visit Dalmeny Quarry. I found in the sandstone rock 
there, numerous concretions of all sizes up to nearly 4 feet in 
diameter. Humbie Quarry I did not visit, as the working of it had 
been given up, and it was full of water. A concretion from 
this last mentioned quarry, sent to me by Mr Hutchison, Professor 
Crum Brown has examined, with the following result : — “ It 
weighs 17J lbs. It consists externally of a thin shell of sandstone, 
and internally of a mixture of quartz and marcasite, closely re- 
sembling the substance of the large ball from Leith. The mean 
specific gravity of the ball was 3 -49.” 
There is thus a sufficient similarity of composition in regard to the 
stone ball and the Humbie concretions, to make it exceedingly pro- 
bable that these Humbie sandstone rocks supplied the stone ball. 
I do not say that Humbie Quarry was the exact spot from which 
the stone ball found at Leith actually came. The sandstone strata 
which occur at Humbie and Dalmeny of course crop out elsewhere 
in the district near South Queensferry ; all that can be said is, that 
