130 M.-Gadon’s mineralogical observations. 
spar, quartz, epidote, and even metallic'substances. ‘sibility before 
the blowpipe is the characteristic of this rock. When destitute of 
fusibility, it belongs to opaque-compact quartz (Hor nstein of the Ger- 
mans. ) 
When crystals of felspar exist in it, in notable proportion, it takes. 
the specific designation of porbhyritic.. The denomination of porphy- — 
ry, being relative to an accidental disposition of elements, is reduced 
to a specific name. _ 
Argilloid. (Thonschiefer, Wer.) 
It has a degree of softness, which permits it to be deeply scratch- 
ed by the knife, complete opacity, and an argillaceots smell, when 
breathed on.. It presents, as.well as petrosilex, a great diversity of 
colours, and has most frequently : a foliated texture. Petrosilex and 
ge unite = be an insensible transition. 
eae: = os | Wacke. (Wern.) 
A conglutination of orbicular, elliptical, and sometimes angi 
kernels or nodules of all sizes, commonly of the same nature as the 
primordial rocks above mentioned, particularly felsparoid, petrosilex,. 
argilloid, and quartz. : 
Amygdaloid. _(Mandelstein, Wern.) 
Round or elliptical kernels of felspar, carbonated lime, quartz, , 
epidote, united.together by a cement, apparently homogeneous. to the 
sight, - : 
Notre.—I have placed ..between. parentheses the name of the. towm. 
where the observation is made. 
The sign = indicates that the mineral i is found j in place. 
The sign O indicates that it is found in loose fragments. 
