304 HENRY G. SMITH. 
This may be considered as an ‘hydraulic limestone, but it is 
doubtful if it could be obtained in sufficient quantities for com- 
mercial purposes. The carbonaceous shales overlying the lime- 
stone contain iron pyrites and barytes in small scales. 
In the crevices of the clay-ironstone nodules, almost pure car- 
bonate of lime has been deposited. 
No signs of organic structure can be detected in the limestone. | 
A slide was cut with fair success, and under the microscope but 
a few particles of quartz can be seen, the remainder being princi- 
pally composed of semi-opaque granules and grains of caicite. 
I am indebted to Mr. W. M. Thomas, of Auburn, for informa- 
tion in reference to this deposit. 
OBSERVATIONS ON SHELL-HEAPS AND SHELL-BEDS. 
SIGNIFICANCE AND IMPORTANCE OF THE RECORD THEY AFFORD. 
By E. J. STATHAM, Assoc. Inst. C.E. 
[With Plates XIV. and XV.] 
[Read before the Royal Society of N.S. Wales, December 7, 1892.] 
A PAPER lately contributed to the Linnean Society by Mr. C. W. 
Darley, gives a description of some remarkable shell-heaps at North 
Creek, on the Richmond River; and the last report of the Mines 
Department, contains a contribution on the same question. 
Believing that the subject is by no means exhausted; and that 
far greater importance and interest are attached to it, than may 
at first sight be supposed ; I request to be allowed to bring under 
notice the information and observations, which, for several years, 
I have been enabled to collect. | 
