102 
middle of the upper one, which just passes into the whiter 
part in small dendritical figures. They are both found near 
aslate quarry. The lower specimen is from Silver-bourn in 
the Isle of Man, where Lord James Murray informs me it 
is found in plenty. I do not know that any use has been 
made of it; when fresh it was hoped that it might serve 
as Fuller’s Earth. 
TAB. CCLII. 
Tretanp affords many curious substances, and seems to 
abound with some varieties of this. The present specimens 
are all from thence, by favour of Dr. Scott of Dublin. The 
beauty of some of them give me an idea of the Lithomarga 
called Terra miraculosa, and may be, perhaps, equally 
beautiful. 
The uppermost specimen is soft, and marks on paper 
readily and smoothly. The middle one is not quite so 
smooth, while the ower one is more earthy and rather 
gritty. It is remarkable for its purplish cast, probably 
caused by a mixture of the red and black Oxides of Iron. 
The middle figure is coloured with red Oxide of Tron, 
holding the little whitish waxy granular fragments of almost 
perfect Steatite, as Trapp sometimes does Zeolite. 
The lower figure is of a brighter purple than the upper 
one, and the. little specks of a similar waxy Steatite give it 
a remarkable and pretty appearance. Some of these, 
Dr. Scott informs me, are of a nature to bear turning in a 
Jathe. They are found in the county of Antrim; some 
near Temple-patrick, accompanying the Basalt in the 
Dykes, which from its crumbling state is provincially called 
Rotten-rock. An exposure to moisture will naturally pro- 
duce this effect on the softer mixed Steatites, as well as 
on Lithomarga. 
