V, A similar mixture, in much finer grains, labelled 

 " Fine heavy Deposit, Kimberley blue ground. 



Sections of the first three specimens were cut and sent to 

 Professor Bonney, F.RS., an abstract of his report upon 

 them is as follows : — 



I, This rock is an actinolitic diabase, and could not be 

 distinguished from specimens obtained from various British 

 localities, where rocks of paleozoic or greater age occur. 



II. This is a rather decomposed basalt belonging toUhe 

 same group as I., but probably from a different mass and 

 altered in a different way. 



These two specimens were analysed with the following- 

 results : — 



I. II. 



It will be observed that these have a very similar com- 

 position, the second differing from the first in containing a 

 considerable percentage of water, and in the fact that its 

 iron is almost entirely in the peroxidized condition. 



III. Of this specimen, the diamond-rock itself, Professor 

 Bonney reports as follows : — 



"No. Ill is evidently a breccia composed of a compact 

 serpentinous rock, of dark colour; the fragments and the 

 paste in which they are embedded apparently being similar 

 in character ; one or two scales of bronzite and a black mica 

 are scattered in the matrix with some small grains of a black 

 mineral of irregular fracture, and one of a brown mineral. 



