xl PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 
some granite, and with the apparent silicification of some bands of 
schist, covered unconformably by sandstone, through which water 
had carried silica to replace the original felspar and mica of the 
gneissic bands below. ‘This view of the metamorphic condition of 
some quartzites Dr. Rubidge regarded as a key to the elucidation of 
certain sections seen in different parts of South Africa, and con- 
sidered by him to be of a very difficult nature, if left to be explained 
according to the usual view of geologists. Thus, in 1858 (Geol. Soc. 
Journ. vol. xv. p. 196), he explained the section of Mitchell’s Pass, 
at the village of Ceres, otherwise than Mr. Bain had interpreted it ; 
and regarded the great sandstone formation of Table Mountain as 
occurring again and again, in great patches of horizontal and uncon- 
formable beds, over the highly inclined schists and gneiss, both of 
the Cape and of Namaqualand, instead of dipping at Ceres down 
below the Devonian rocks of the Bokkeveld; and thus he made the 
schistose rocks of Cape Town, of the Bokkeveld, George, and southern 
Uitenhage (whence he got Devonian fossils) to be all of the same 
date. Certainly a great advance was made in proving the continu- 
ation of the Bokkeveld schists into the last-named district; but 
whether the schists and slates of the Cape come into the same cate- 
gory still requires careful inquiry. 
Examining the neighbourhood of the Zuerberg, in occasional 
journeys, Dr. Rubidge endeavoured to throw light on the stratifica- 
tion and structure of that country, showing that the Lower Ecca 
beds are probably of Devonian age. For the illustration of his 
views on this matter, he sent several series of rocks and fossils to 
the Geological Society of London, and he communicated papers on 
the subject to that Society, to the ‘ Geologist,’ to the British Asso- 
cion, and to the periodicals of Port Elizabeth. In 1864 he visited 
England, and travelled to the north with the special view of study- 
ing schistose and quartzose rocks like those of the Zuerberg. He 
brought with him many new fossils, of Secondary age, from the 
Uitenhage district, and went to considerable expense in getting 
them properly examined and determined, intending ultimately to 
produce a general work on the geology of the colony. ‘The fossils 
constituted a valuable addition to the South-African collection in 
the Geological Society’s Museum, and were fully described, with 
illustrations, in the Society’s Journal, by Mr. R. Tate, in 1867. 
So long ago as 1854, Dr. Rubidge wrote to his geological corre- 
spondents in London on the subject of aérial denudation, which had 
not then received so much attention from European geologists as it 
deserved. In 1866 he reproduced the chief points of his letters in 
the ‘Geological Magazine, No. 20, bringing forward evidence of 
the enormously extensive and long-continued denudation of the 
interior of South Africa, subsequent to its leaving the sea and 
since the lacustrine deposits of the Karoo formations were drained 
dry. 
As an observer and as a generalizer, then, Dr. Rubidge was ener- 
getic and bold, adding much to the store of geological facts and 
thought, though working hard throughout in his professional prac- 
