EL2 NOTE ON PRECEDING PAPER. 
It is very generally granted that lateral secretion has played a 
very large part in the filling up of veins, and that the lime, among 
other minerals, has been obtained from the surrounding country 
is therefore more than probable. Let me then refer to Mr. 
R. L. Jack’s Report on Charter’s Towers (1879), p. 15, from 
which I take the following extract :— 
“ Occasionally, where the ‘greywackes’ are fresh, and seen to contain 
little iron, they somewhat resemble blue limestone, while their joint surfaces 
are sometimes coated with calcspar. These circumstances havé led, in at 
least one case, to the erection of a kiln, and the experiment of burning a 
kilnful of the grey wackes for lime.” 
Without absolutely saying that the greywackes are the source 
of the calcite in the lodes, I think this a more probable theory 
for the origin of the latter than its derivation from the so-called 
Scolecite ; and I might further point out that Hornblende, which 
is not infrequent in the Charters Towers rocks, is another mineral 
containing a considerable percentage of lime. 
REPLY TO THE PRECEDING NO@iia@e 
Eo) Ba cLIN DOWN, AnRoopm ie 
BY 
A. W. CLARKE, Government Mineralogical Lecturer. 
In this Mr. A. W. Clarke stated as follows :— 
1.—That both Scolecite and Laumontite crystallized according 
to the same system, and that owing to this fact, and also because 
of the variations of crystalline form, which both Laumontite and 
Scolecite exhibited, it would be difficult to distinguish by this 
physical character between the two minerals. 
2.—That Scolecite, according to Dana, sometimes vermiculated 
before the blow-pipe, but not always. 
3-—That the chemical composition of the mineral in question 
was different from that of Laumontite, as might be seen on 
comparing the analyses now furnished (vzde pp. 109-10) with those 
given as of Laumontite by Phillips, in the ‘“‘ Mineralogy” of that 
author. Here we were informed that the latter mineral according 
to different analyses contained :— 
(1.) (2.) (3-) (4.) 
SiO,  < : » 48:3 52:47 50:34) =aso100 
Mis) OVS : 2) (22.7, 22 "50" 21AGe Ne eAeae 
Cal@rr se: : ee eB 4 TTA iene 
Ie UAW ON he : 2) 16:0) "5's 16i15) eneaae 
