134 Transactions of the South African Philosophical Society. 
as these, extend over a number of years, it is better far by the 
employment of one uniform method throughout the whole series, to- 
ensure that the results shall be strictly comparable with one 
another, than to risk the almost certain unconformity likely to be 
produced by the adoption of new methods: hence it is advisable 
rather to adhere throughout to the method of analysis resolved on 
at the outset, and to state that method clearly, than from time to 
time to adopt the new and improved methods which the advances of. 
scientific thought and investigation may develop. 
The portion of the Colony selected for our operations happened 
to be identical with that traversed a year or two later by the 
Geological Survey, and from our standpoint it is not a little to 
be regretted that that work did not precede ours, as we would 
have been greatly assisted thereby. The portion I allude to com- 
prises the south-western districts of the Colony extending from 
St. Helena Bay to Mossel Bay, and is made up of the divisions 
of Malmesbury, the Cape, Caledon, Bredasdorp, Swellendam, 
Robertson, Riversdale, and Mossel Bay. Since then we have 
extended our operations to the Divisions of George, Knysna, 
Uniondale, Oudtshoorn, Prince Albert, Ladismith, and Worcester, 
while in the Eastern Province the Divisions of Cathcart, Komgha, 
Butterworth, Willowvale, and St. Marks have been dealt with. 
I say again, it is a pity that at the outset of our investigations 
we did not have the advantage of the map published with the 
. 1897 Report of the Geological Commission, covering as it does 
exactly the area of our operations during the years 1894-96. It 
is with that area I propose to deal in the present paper, and it 
must be remarked that even now the area surveyed has not been 
sufficiently extensive to allow of general conclusions being drawn, 
and therefore it is perhaps somewhat unwise to venture upon 
statements which time may yet disprove. : 
I have profited by Dr. Corstorphine’s kindness in being able, as it 
were, to superimpose upon the maps* showing the localities whence 
our samples were collected, the map published with the Geological 
Commission’s report, illustrating the geological formation in the 
south-western corner of the Colony. As every endeavour was used, 
when collecting the samples, to locate the site whence each one was 
taken as accurately as possible, we have thus been enabled to refer 
every sample to the underlying geological formation with a view to 
deducing conclusions from the results of the analyses. | 
The area with which I propose now to deal includes part of the 
divisions of Malmesbury and the Cape, the Caledon, Bredasdorp, 
* Reduced divisional maps were shown when the paper was read. 
