146 Professor E. H. L. Sc/iu-arz — Secular Earth-Creep. 



In tlie DeTonian rocks we have in Soiith Africa a peculiar assemblage 

 of forms characterized by a small Brachiopod, Leptoccelia flabcllites^ 

 Conrad. "When these were first sent home by A. G. Bain, Rupert Jones 

 at once wrote back saying that they were the same as the fossils then 

 recently brought back from the Falkland Islands by Charles Darwin. 

 Eecent work has proved the correctness of this view, and not only in 

 the Falkland Islands, but the Lower Devonian fossils from the 

 Argentine, Brazil, and Bolivia in South America, and the eastern 

 portion of North America, are remarkably alike, and, on the other 

 hand, as remarkably distinct from the European Devonian fossils. 



To make sure that our South African fossils were identical and not 

 merely similar to the North American forms, I submitted a small 

 series from the Bain Collection in the Albany Museum, Grrahamstown, 

 to Dr. J. M. Clarke, who very kindly examined them and replied as 

 follows : — 



" The specimens of Leptoccelia jlcihellites are entirely in accord 

 with the usual expression of this species as it occurs in the New York 

 Oriskany, the Gaspe sandstone of Eastern Quebec, and the Lower 

 Devonian sandstone of Central and Southern Brazil and of the 

 Falkland Islands. There are some variations in this species which 

 might upon close analysis serve to exhibit definite stratigraphic or 

 time values. We find, for example, in certain Oriskany beds in this 

 State multitudes of more diminutive forms which seldom attain the 

 normal average size as expressed by your South African specimens. 

 On the other hand, in the Grand Greve limestones of Eastern Quebec 

 the species attains quite extraordinary dimensions, and it is interesting 

 to observe that this large size is reached in a calcareous facies, and the 

 same effect is noticeable in other Eo-Devonian species which are most 

 commonly known in the arenaceous sediments." 



A large part of these Lower Devonian strata are sandstones with 

 shales and limestones interbedded, and the whole aspect of the series 

 is that of a shore deposit. I cannot speak of the direction from which 

 the sediment was carried except in South Africa, where the sandy 

 beds occur towards the north, and their place is taken by shale beds to 

 the south, and there can be no question, therefore, that the land in 

 these times lay to the north. We can, however, plot roughly the 

 shore-line of this ancient continent on the south and western shores. 

 In the north we know very little yet of the beds ; the actual shore- 

 line is submerged beneath the ocean in Europe, and in North Africa 

 the exposures in the Sahara are too isolated and as yet not suflSciently 

 explored to enable one to plot the shore-line. It is true that 

 Professor E. Haiig has described two characteristic South African 

 fossils, including Leptoccelia flabellites, from Tassili in the French 

 Soudan, which were brought back by the Foureau expedition. I have, 

 of course, only seen the photographs published with the description of 

 these beds, but the fossils do not to my mind resemble the Soutli 

 African ones. However, accepting Professor Hang's determinations, 

 the occurrence of the Leptoccelia flahellites fauna in the Soudan 

 would indicate that an inlet of the shore of the Devonian Atlantis 

 passed somewhere in the neighbourhood. The rest of the Saharan 

 Devonian fossils are plainly European, and suggest that there was no 



