PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 109 
means so difficult as their want of form and general similarity of appearance 
would at first sight lead one to suppose. 
Delessite can be distinguished from chloropheite by its dull lustre, its 
minutely granular structure, its opacity, and its colour—in the field ; and 
rapidly in the laboratory by its much higher gravity, its much smaller loss at 
212°, and much smaller total content of water. 
From the specimen of Hullite found at Kinkell, I could not by physical 
properties undertake to distinguish it ;-the darker varieties of Delessite 
at least much resembled that specimen. 
From saponite, Delessite can be distinguished by its dark colour and 
granular structure and its opacity; and in the laboratory by its high gravity 
and its water. 
From celadonite it could not be distinguished either by its structure or 
opacity, or by its gravity, or satisfactorily by its water content ; but its colour, 
and its solubility in acids, at once suffice to separate the two. 
Chloropheite is readily recognised ; when fresh it resembles a green jelly,— 
when weathered it equally resembles drops of asphalt. 
The Kinkell Hullite resembles a dark Delessite, and therefore does not 
resemble chloropheeite. 
Saponite, in its usual green form, is easily known; its extreme softness, 
greasy lustre, great translucency, and soapy structure suffice to define it in the 
field; the extreme readiness with which it parts with and regains so large a 
quantity of water equally suffices in the laboratory, while its low gravity is of 
itself characteristic. 
The white variety is by no means so readily identified; halloisite, conite, 
the magnesian carbonate of lime, agaric mineral, and a peculiar superhydrated 
vein-serpentine, all closely resemble it. 
Celadonite may at once be known by its insolubility in acids; its loose 
granular or mammillated structure, its perfect opacity, and brilliant colour, 
are likewise well-marked characters. 
Such are the minerals occurring in Scotland, which are without question to 
be referred directly to one or other of the above species. I now note certain 
which cannot be so unhesitatingly classed.under any of these heads, and two 
which appear to be new. 
1. About one hundred yards above the bridge of Cally, in Perthshire, a 
singular bedded boss of friable trap protrudes out of the north bank of the 
Ardle. This contains amygdules from the size of shot to that of a bean, filled 
with a dark, greenish-brown, soapy substance, which is much impregnated with 
both calcite and chalcedonic quartz. Its structure is minutely granular. 
