

Fig. 4. — Glacially striated diabase, made in early Permian 

 time. Vaal River north of Kimberley, South Africa. 

 Photograph by W. M. Davis. 



Fig. 5. — Lower Cambrian quartzite, striated in early 

 Permian time. Inman Valley, South Australia. 

 Photograph by T. W. E. David. 



