528 PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 
From Silurian Slates. 
21. Specimen from JAMESON TorRy’s collection ticketed “ Lead hills.” This 
was nearly white, tough, but flexible ; seemed formed of matted fibres. 
On 19 °8 grains— 
Silica, : ; ; ce wil 
Alumina, . ; : . £2981 
Ferric Oxide, . ; : Oe 
Ferrous Oxide, . » «d2 286 
Manganous Oxide, . od 487 
Lime, : : sta pee. 
Magnesia, . ; é «plies 
Water, . ; : ew aly 
98-997 
Loses 5°96 per cent. of water in bath ; contained some calcite. 
From Old Red Sandstone. 
22. The conglomerate of the “ Old Red” at the Tod Head, in Kincardine- 
shire, contains a singular vertical vein of about one foot in width, which consists 
for the most part of calcite. This vein runs about S.E. and N.W. Towards 
its centre there is an almost continuous sheet of mountain leather. This sheet 
on the one side has always cockscomb crystals of baryte penetrating it ; on the 
other there is calcite alone. Here and there fragments of the conglomerate are 
matted into the mass of the leather. : 
. The appearances convey the idea that the mountain leather was the last in 
the formation. A cross vein in the neighbourhood, formed of lustrous calcite, — 
carried imbedded crystals of Laumontite. 
Colour white, more or less stained with iron oxide. Tough, and difficultly 
flexible. 
On 17 °3 grains— 
Strontian. 
Silica, . ; ; .. 52°483 oi 65 
Alumina, .° : as 62.326 9-505 
Ferric Oxide, . : 6 oe 
Ferrous Oxide, 2a) 5+ 805 
Manganous Oxide, 2-878 some. 
Lime, . oH) re” A 84o 10-005 
Magnesia, . : .- 11°954 2° 065 
Water, : : eh 2 DAR 
99,-.396 LOOM 73 
Loses in bath 5° 995 per cent. of water ; insoluble silica, 1-618 per cent. 
be \ 

