NOTE ON PRECEDING PAPER. PE 
INQUGE CO ING A. Pave BIR 
ENTITLED 
OWN (ee? NEN BARA. “"S COLEC TV 
Oc CL Re NN GasO DL. GR AN TE, 
CHARTERS TOWERS*.” 
BY 
E. B. LINDON, A.R.S.M- 
As regards the mineral sent from Charters Towers by Mr. A. W. 
Clarke, and considered by him to be Scolecite, I beg to differ 
from him in this determinaiion, while I confess to having given 
the subject much less attention than he evidently has done. 
Scolecite differs from Natrolite in containing lime in place of soda; 
according to Dana, it is found only in trap and amygdaloidal 
rocks; furthermore, its name is derived from the Greek word skolex 
(a worm), referring to its blow-pipe re-action, for before the blow- 
pipe Scolecite curls up like a worm, fusing to a voluminous, frothy 
shining slag (G. J. Brush). Scolecite, as a rule, if not always, has 
its rhombic glassy prisms longitudinally twined, as is shown by 
the meeting of two ranges of striae at an angle, or near the central 
line of opposite planes (Dana) and as seen in the sample of this 
mineral exhibited. ‘These characters are absent from the mineral 
sent by Mr. Clarke, which seems to me to more nearly coincide 
with Laumontite, another hydrous silicate of lime and alumina. 
Laumontite becomes opaque on exposure and readily crumbles 
(wherein it greatly resembles Mr. Clarke’s specimens), owing to 
loss of water. Further, Laumontite, before the blow-pipe, fuses, 
emitting air-bubbles, to a white translucent slag (Brush), and this 
re-action I have obtained from Mr. Clarke’s mineral. 
But, even if I am wrong, and the mineral be really Scolecite, 
the presence of calcite in the Charters Towers veins is not solved 
thereby, for Scolecite is a derived mineral, and the same question 
arises, only in its altered form it becomes: whence was the lime 
for the Scolecite obtained ? 
* This Note, and Mr. Clarke’s reply thereto, although read at the 
September meeting of the Society, are inserted here for convenience of 
reference.—Eb. 
