ANNIVERSARY ADDRESS. a7 
geologically newer than the Wianamatta Shales and Hawkesbury 
Sandstone ; (2.) That the eruptive rocks, when intruded into the 
sedimentary, worked their way to the surface by dissolving the 
overlying rocks, and absorbing the greater part of their material, 
instead of wedging them apart laterally. This is probably the 
true explanation of the great variation observable in the mineral 
constitution of the basaltic intrusion at neighbouring localities. 
All were derived in the first case probably from a magma of uni- 
form chemical composition; but this became subsequently blended 
at the various points of intrusion with a variable quantity of 
sandstone and clay shale derived from the surrounding sedimentary 
rocks. An examination by Professor David and Mr. A. J. 
Prentice, B.A., of the Geological Fault at Lapstone Hill, proves 
that great disturbance in the stratification of the earth’s crust 
to resemble a monoclinal fold rather than a fault, the strata of 
Hawkesbury Sandstone being bent down sharply to the east, 
between Lapstone Hill and Emu Plains. Until the measure- 
ments are completed, it will be impossible to state whether or not 
the folding culminated in an actual shearing of the strata. With 
the kind assistance of the Department for Mines, a new geological 
map has been prepared of New South Wales. A map of Australia 
has also been prepared in this Department, showing the area of 
the artesian water-bearing formations and the position of all the 
principal natural springs, and the artificial wells and bores. 
Dr. Ramsay has kindly supplied the following list of papers 
published in the “ecords of the Australian Museum” during 
1891 :— 
On a New Species of Pteropine Bat from the New Britain Group. 
By E. P. Ramsay. 
Notes on the Disappearance—Total or Partial—of Certain Species 
of Birds in the Lower Lachlan District. By K. H. Bennett. 
Description of a New Fish from Lord Howe Island. By J. 
Douglas Ogilby. 
Supplement to the Catalogue of “ Nests and Eggs of Birds found 
breeding in Australia and Tasmania. By A. J. North. 
