240 PROF. A. H. GKEEN ON THE GEOLOGY AND 



discouraging circumstances, he has materially enlarged our know- 

 ledge of the detailed geology of the Cape Colony *. 



But though I was all along following the footsteps of such ahle 

 forerunners, I believe I have succeeded in adding some little to the 

 stock of our knowledge in South-African geology, and have done 

 something towards clearing up points which were heretofore doubt- 

 ful. In this belief I now offer the results of my work to the 

 Society. 



The grouping of the South- African rocks which I have been led 

 to adopt is as follows : 



(Volcanic Beds, 9 d. 

 Cave Sandstone, 9 c. 

 Red Beds, 9 h. 

 Molteno Beds, 9 a. 

 8, Karoo Beds. 

 7, Kimberley Shales. 



Great Unconformity, 

 6. Ecca Beds. 

 5. Dwyka Conglomerate. 



Unconformity. 



4. Quartzites of the Zuurbergen, Zwartebergen, and Wittebergen. 



3. Bokkeveldt Beds. 



2. Table-Mountain Sandstone. 



Great Unconformity. 



1. Slates and intrusive Granite of the neighbourhood of Cape 

 Town (Malmesbury Beds). 



* Prof. T. Rupert Jones, who has a very wide acquaintance with the lite- 

 rature of South-African geology', points out to me that other observers besides 

 those mentioned in the text have written on this subject, and mentions specially 

 W. B. Clarke (1841), Dr. Atherstone, G. W. Stow, J. Shaw, W. Prosser, R. N. 

 Eubidge, Piibner, Hochstetter, and others. The last two words show that even 

 with these additions the list is incomplete. It would indeed be hardly possible 

 to compile a bibliography which should be even approximately satisfactory; for 

 many of the contributions to the geology of South Africa are scattered through 

 newspapers or Colonial periodicals which are difficult or impossible of access 

 to the English reader. The same friendly critic remarks that many facts are 

 recorded without acknowledgment in the following pages which have been 

 noticed by previous observers, and that a false impression may thereby be 

 created in the minds of my readers that I claim these as discoveries of my own. 

 I am very thankful for the warning, and have done my best to guard against 

 the mistake which it was intended to prevent by availing myself freely of the 

 copious list of references wliich my friend has supplied. To make my story 

 conjplete, 1 have had repeatedly to supplement my own observations by those 

 of previous workers in the same field. In the larger matters I trust that I have 

 been able to indicate the sources from which I derived my information. There 

 are besides points of minor importance, which have been commented on over 

 and over again. I should not have thought it necessary, under any circum- 

 stances, to call attention to every writer who has mentioned these ; for the 

 reason jusT given this would not always have been possible. 



