2 Professor Seeley, — Some Scientific [Sept. 16, 



in which the rocks have been crushed together laterally by this 

 intense power coming from the south. And when I had passed through 

 this range (where I found the ancient limestones completely cry- 

 stallised, limestones which themselves have been worn into pebbles 

 and laid down as sure deposits, cemented into marble, which pebbles 

 had acquired crystalline structure,) then upon these marbles I found 

 altered rocks, ancient clays greatly altered, now converted into the 

 condition of cleaved slates by the pressure, and upon this sandstone, 

 rested and changed into quartzite, stones formed of pebbles in the 

 same way, rolled down ancient shores, which pebbles were themselves 

 bound together by a cement, formed in consequence of the intense 

 heat, due to the process of compression. I then turned towards the 

 rocks in the Prince Albert region, to those newer rocks which rest 

 upon the Zwartberg, and which form the base .of the series which we 

 Jaiow as the Karoo rocks. Now what those lower beds may be 

 which intervene between Prince Albert and Zwartberg, I will not 

 now stop to discuss, but I will say that just to the south of Prince 

 Albert you come upon a marvellous rock which has amazed every 

 one who has examined it, and defied the skill in interpretation of 

 every one who has brought the powers of the microscope to bear upon 

 it, and that rock we know as the Ecca conglomerate, which was 

 sometimes called by your earlier geologists, (especially by Mr. 

 Andrew Bain, that wonderful genius to whom we owe the first 

 .interpretation of the geological structure of Africa), the trap con- 

 glomerate, and presents the aspect of a trap on the one hand, and 

 a conglomerate on the other. But when we come to consider what 

 variance there is in these terms, that a trap means a lava flow forced 

 out from a volcanic centre flowing over the surface of a country, 

 and that a conglomerate means a rock rolled into the form of pebbles 

 by the action of the breakers on shore, which boulders have sub- 

 sequently been united by some kind of cement, you will see that the 

 old name of " trap conglomerate " implies such a contradiction that in 

 ■the interests of science we lay it one side, fully recognising the dis- 

 crimination which recognised its true character, and we adopt the 

 name " Ecca conglomerate " instead. Now by this term Ecca con- 

 glomerate, which I believe we owe to Mr. Dunn, we mean a rock in 

 which you find rounded boulders and angular fragments of all kinds 

 of rock, for the most part crystalline, and very frequently perfectly 

 altered from their original condition, and embedded in a cement 

 which resembles different forms of volcanic ash (ash such as that which 

 was thrown out in the wonderful eruption of Krakatoa), which 

 apparently fell upon a shore where pebbles and boulders were brought 

 down in great quantity, and which have become cemented into a rock, 

 which now, after the long lapse of ages, presents the aspect of a trap, 



