Fossil Floras of Cajjc Colony. lOo 



pliytons have probal)ly l:)een formed by swirling water -which has 

 left an impress in the form of obliquely striated and prominent 

 ridges (pi. xiv.) on the hardened sediment of an eddying stream 

 that flowed through the sand by a narrow vertical channel. I 

 ought to add that I have not made an extended examination of 

 Spirophytons from other localities, but as regards the South African 

 specimens my view is that they do not represent the remains of 

 plants. 



Plate XIV., fig. 1 (57a). 



The drawing shows the surface-view of a specimen, 13 cm. by 



12 cm., in which the Spiropliyton characters occur on different 

 levels of the rock, but with no apparent regularity. In the centre 

 {a) there is an approximately cylindrical and obliquely placed cast, 

 from which the curved ridges and grooves radiate over the surface 

 of the stone, sloping slightly downward from the central point. 

 This axis may well be the cast of a central channel in which the 

 swirling water passed or flowed through the sand. As shown in 

 the figure, the surface of the rock is very uneven ; at c several 

 prominent ridges are seen covered by numerous oblique secondary 

 ridges. Similar obliquely striated and prominent ribs are shown 

 also at i at a higher level. There is no trace of any carbonaceous 

 matter. The strongly marked and prominent ridges form a striking 

 feature, and cannot, I believe, be explained on the assumption that 

 they have been formed by the impress of a leaf-like organ. 



Plate XIV., fig. 2 (12a). 



View of a specimen, 12 cm. broad, showing a portion of a Spiro- 

 pliyton impression. The centre from which the curving ridges 

 spring was probably close to the left-hand end of the drawing, 

 where the surface of the rock stands at a slightly higher level. The 

 edge of the impression (right-hand side of the figure) is fairly well 

 defined, and forms a definite boundary between the Spiropliyton 

 and the rock matrix. The surface is undulating, with occasional 

 broad curved folds which are traversed by numerous parallel ridges 

 less prominent than those shown in fig. 1. At d a few parallel ridges 

 are seen following a course oblique to the general trend of the 

 narrow ribs and grooves. 



Other specimens : 1. A specimen from i mile South of Ladismith, 



13 cm. by 13 cm., showing a truncated prominence in the centre, 



