134 E. H. L. SCHWARZ 
range of rocks of widely separated ages; there is no evidence of such 
faulting, and although the rock is a typical lava, fine-grained to glassy 
in structure, and generally full of steam cavities, Dr. Rogers and myself 
were forced to the conclusion that the rock was an intrusive one and 
came into position after the earth movements affecting the Matsap 
beds had taken place. 
About 30 miles in a southeasterly direction, reckoning from the 
southern extremity of the Zeekoe Baard mass, there is a second 
outcrop of amygdaloidal melaphyre on the eastern portion of the farm 
Jackals Water, and on the western part of the farm Prieska’s Poort. 
The outcrop is elongated about 6 miles long and 14 miles wide, trend- 
ing northwest, the direction of strike of most of the Palafric rocks in the 
Prieska district. On the northeastern side the melaphyre is bounded 
by the granite of Prieska’s Poort, and on the southeastern side by 
the Keis quartzites on the farms Jackals Water and Uitzigt. 
Similar rocks in the neighboring districts which appear most 
certainly to be intrusive have strengthened the view that the Zeekoe 
Baard and Prieska’s Poort amydaloids are instrusive, but against 
this we have the steam-holes and agglomerates—clear indications 
of volcanic origin. 
If we accept the volcanic origin, then we must imagine that from 
a central vent or fissure some extremely fluid lava was poured out, 
which flooded all the low-lying country, wrapped round the hills, 
and finally cooled as a plain of lava. - No known volcano fulfils these 
conditions, and from what we know of lava we would be inclined to 
state that such a mass could not be suddenly ejected at any one time, 
but would rather come up in separate flows, each of which would 
travel outward and downward and would cool long before it could 
wrap round the end of a range of hills such as the Ezel Rand, in the 
manner of a perfectly liquid substance. Then again we find the agglo- 
merates at the periphery of the Zeekoe Baard mass, and here, also, to 
the north, there is evidence of thrust. 
In whatever light we look upon these Prieska outcrops of amyg- 
daloidal lava, confining our ideas to a terrestrial origin of the material, 
we come upon insuperable difficulties, but directly we admit the 
possibility of the fall of a meteor sufficiently large to melt up a portion 
of the earth’s crust, all these difficulties vanish. ‘The sudden develop- 
