166 F. R. Cowper Reed—Fauna of the Bokkeveld Beds. 
STRATIGRAPHY. 
The stratigraphical relations and sequence of the beds comprised 
in the Bokkeveld Series have been carefully observed in many parts of 
the Cape, and the succession of the beds, where typically developed, 
has been recently given by Rogers (1), and may be concisely expressed 
as follows (in descending order) : — 
SHALES ... 58 -.» 800 ft. \ 
Rounnis Santn aaonaienal aloud eee beds are Bouse uel defined oa lower 
SHADES) gum Ice emmcOUtte nee “tithes | 
TuirpD Sanpstone ... 100 ft. ian! (pleiiiicsteina La 
SHALES ... ... about 350 ft. Often micaceous, with thin interbedded quartzites 
and usually few fossils (Lingula, Nuculites, 
crinoid stems, a trilobite, Conwlaria, plant- 
remains). 
Szconp Sanpstone ... 400 ft. Many shale beds. Few fossils; Spirifer 
occasionally abundant. 
SHALES ... aa 100-800 ft. Fossiliferous (especially starfish, but also many 
species occurring in lower shales). 
First SANDSTONE ... 150 ft. Slightly calcareous, containing many fossils 
locally, especially Spirifer and Leptocelia. 
Often containing nodules, and many fossils 
SHALES AND ae. about 300 ft (Phacops, Homalonotus, Leptocelia, Spirifer, 
SANDSTONES Chonetes, Orthothetes, Orthoceras, Bellerophon, 
Nuculites, and Crinoids). 
A definite sequence of fossil forms in the successive beds might 
reasonably be expected, but Schwarz (2, p. 347) has recently declared 
that in spite of long and determined efforts he has failed to recognise 
any zonal succession or assortment of species in the series. This is 
distinetly disappointing, as in the homotaxial Devonian of South 
America certain, though not very strongly marked, faunistic differences 
are noticeable. A more or less decided difference in the faunistic 
facies can, however, be observed in the Bokkeveld Series, which is 
connected with the lithological character of the rocks; thus the shales 
possess a different assemblage of fossils to the sandstones, but this 
difference is seemingly due to bionomical causes and to the nature of 
the environment as expressed in the sedimentation rather than to 
a chronological replacement of types and a succession of different 
faunas each of stratigraphical significance. Accordingly we find 
ourselves forced at the present time to regard the fauna of the entire 
Bokkeveld Series as composing a simple and stratigraphically indivisible 
whole, even the faunules being scarcely distinguished as yet, though 
future work may modify this conclusion. 
It has, indeed, been observed that there are peculiarities in the 
horizontal distribution of some of the organisms; for instance, the genus 
Homalonotus predominates in the western and ‘northern, the Spir ufers 
in the central, and the ornate Phacops in the eastern outcrops, according 
to Schwarz (2). But to what these facts point is at present uncertain. 
From the foregoing remarks it will be seen that in the present state 
of our knowledge we must include all the fossils from every locality 
and bed in the same list, and this principle is accordingly followed. 
Composition oF THE Fauna. 
The various zoological groups of organisms are treated here 
separately in order to discuss conveniently the special characters of 
various members and of the general features of each group. 
