Mines and Mineral Statistics. 
i2g 
moisture in the stone evaporates on coming to the surface, 
the salt held in solution crystallizes therefrom, and by the well- 
known power which the mimite crystals exert when forming, they 
force asunder the grains of sand, and thus by degrees slowly disin- 
tegrate the rock ; whereas the upper surface of the atone is exposed 
to the rains, which continually wash away the salt as it appears, 
and so prevent its crystallization. The remedy should be either 
to coat the surface of the stone in dry weather with some material 
impervious to water ; or to reject stone that contains over a 
certain percentage of salt. A very simple process at once 
suggests itself for ascertaining the quantity of salt, by washing a 
certain weight of powAered stone, and then, after filtering the 
solution, obtaining from the latter the salt by evaporation. Such 
trials could be easily conducted, and would afford valuable infor- 
mation for architects and building contractors. 
In the rocks in Sydney Harbour the Cleithrolepis granulatus 
has been found. 
In many places the sandstone assumes a columnar structure 
similar to that so frequently to be observed in basalt. Some 
good specimens are exhibited showing the hexagonal columns ; 
these I obtained close to a dyke near M. La Perouse Monument 
at Botany Heads. 
No coal seams of value occur either in the "Wianamatta or 
Hawkeshury series. 
Upper Coae Measures. 
Almost all the fossil plants characteristic of the upper coal 
measures are exhibited, and were obtained from the beds at New- 
castle, Bowenfels, and Wollongong. They include the abundant 
Glossopteris Browniana, Gloasopteris linearis, Phyllotheca Austra- 
lis, Phyllotheca Hookerii, Sphenopteris, Vertebraria, Conifers, 
seeds and stems of trees ; one dendrolite is a section of a silicified 
tree-stem, about 18 inches in diameter. 
The splendid specimens I obtained from the Western Coal 
Fields are very perfect, amongst them may be seen several species 
of Glossopteris, a very largo A^ertebraria, and a peculiar peltate 
leaf, apparently neAV. AVith these I would draw attention 
to the fine impressions of an undescribed species of Conifer, Avhich 
Avere found in the coal seam on the property of Mr. A. BroAvn, 
CoerAvull, near Lithgow A^alley ; also to a new fossil plant which 
I collected from the coal measures at Newcastle. Professor 
Dana, of America, Avho has examined the latter, pronounces it to 
he different from any plant he had yet seen. At Newcastle I 
have seen fragments of the frond of a Sphenopteris fern, Avhich 
p 
