PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 81 
THE SAPONITES. 
DELESSITE. 
From Igneous Rocks of Old Red Sandstone Age. 
1. At St Cyrus, north of Montrose, there is a great cliff (a raised beach 
being between it and the sea) composed of thick beds of conglomerate, with 
occasional interstrata of amygdaloid. This amygdaloid is studded with agates 
filling long pipe-shaped steam-holes. These agates are for the most part coated 
with light-green, translucent, vitreous-lustered celadonite ; but the steam-holes 
themselves are also frequently entirely filled with Delessite. 
The structure of the Delessite is scaly,—perfectly recognisable here from 
the large size of the scales; the colour is sap-green, sometimes passing into 
red. It is translucent, and scratches easily with the nail. 
The specific gravity is 2° 652. 
The red variety is much of the colour of brick, and seems sometimes pseudo 
after natrolite ; this may be bole (plynthite). 
Some specimens of the green variety on being pounded become brownish- 
red during the progress ; this seemed to be partly due to the presence of minute 
quantities of the red mineral. 
Of the pure green 1-3 gramme yielded— 
Silica, . d *419 
From Alumina, ‘006 
*425 = 32 * 692 
Alumina, ; : . &5°435 
Ferrie Oxide . . . ~4#397 
Ferrous Oxide, " : 6° 624 
Lime, , : , ; ‘861 
Magnesia : « 28° 769 
Water, , : : . 138°245 
100 + 023 
Of the above water, 2° 774 was lost at the temperature of 212°. 
2. In the dense igneous rock above Bowling Quarry, on the Clyde, and 
between it and Glen Arbuck, this mineral occurs of a close, minutely-foliated 
structure, and a very dark-green, almost black colour. It is softer than the 
nail and has a specific gravity of 2:573. Its streak is pale green. 
