18 W. H. WARREN. 
scopic sections of the dykes, prepared in the Geological Laboratory, 
show that the dolerites of which they are composed contain 
sanidine, and they may therefore be possibly related to the mass 
of intrusive syenite near Mittagong, which contains a similar 
felspar. 
Several interesting sections of glass slags from the Camperdown 
Glass-works, Sydney, have lately been prepared by the students. 
These sections show some well-developed microlites arranged in 
sheaf-like or fibrous radial aggregates, closely resembling similar 
structures in lavas. 
An examination of a collection of fossils, obtained some years 
ago in the Vegetable Creek District of New England, has led to 
the discovery in them of the shell Productus, so that a very large 
area occupied by rocks containing these fossils will now need to 
be coloured on the geological map as Carboniferous instead of 
Silurian, as coloured at present. This alteration will harmonise 
the geological maps of New South Wales and Queensland along 
the valley of the Dumaresq River, where previously a great dis- 
crepancy existed. 
A recent examination in company with Mr. E. F. Pittman, the 
Government Geologist, of the country in the neighbourhood of 
Rydal, has led to the discovery that Lepidodendron occurs in situ 
in the Devonian rocks associated with Spirifera disjuncta, a shell 
of undoubted Devonian age. Mr. Clunies Ross, B.Sc., of Bathurst, 
has recently made a similar discovery nearer Bathurst, and thus 
the question as to whether Lepidodendron in New South Wales 
descends into Devonian strata or not may be considered as 
definitely settled. These discoveries confirm the views as to the 
geological age of the above plant in New South Wales, held by 
the Rev. W. B. Clarke, F.r.s., and the late Government Geologist, 
Mr. C. 8S. Wilkinson, F.a.s. 
Astronomical Photography.—The work accomplished at the - 
Observatory under Mr. H. C. Russell, Astronomer of New South a 
‘Wales, may be briefly summarised as follows :—The past year has 
