PROBABILITY OF METEORITES HAVING FALLEN 135 
ment of a large quantity of liquid lava, the permeation throughout 
of steam holes from water contained in the rocks melted, the ridging 
up of portions of the periphery of the mass, the absence of true 
volcanic ash, but the great development of crushed up material 
entangled in molten rock—all these phenomena receive an adequate 
explanation on the meteor hypothesis. That the masses of lava 
often tail out into apparent dykes can be readily accounted for from 
the fact that earth movements have gone on since the development 
of the lava and such dyke-like extensions would be portions drawn 
out by crushing just as a crystal of felspar is drawn out in many 
gneisses. 
Against the general acceptance of such a theory there is the objec- 
tion that certain of the Archaean and early periods are characterized 
by just such volcanic rocks as are to be found in Prieska, great masses 
of lavas and clastic igneous rocks of all sorts. If any of such volcanic 
areas owe their rocks to meteors, it is certainly probable that the 
masses of planetary matter were grouped in swarms which would 
produce the same effect on the whole as a general outburst of great 
volcanoes over the earth. Each swarm would gradually discharge 
the individual bolides as the earth in its course round the sun came 
within attracting distance, and when the swarm was exhausted or 
passed out of reach of the earth’s attraction, then there would be 
a secession of the production of these igneous rocks and normal 
sedimentation would take place. 
In conclusion I must repeat that I do not contend that I have 
proved the meteoric origin of the amygdaloidal melaphyres of Prieska; 
but I maintain that the facts that we now know force us to take into 
consideration, when dealing with these extensive tracts of molten 
material on the surface of the earth, their possible origin from the 
collision of large meteorites. Everywhere we look in the older rock 
systems, we find enormous deluges of igneous material which are 
difficult to explain on the theory that the mass came from the interior 
of the earth, such as, for instance, the Bushveld igneous complex in 
the Transvaal; the object of this paper is to point out a possible 
cause in many cases, which so far has not been recognized. 
