THE BANKS OF THE DWINA 



photographs, and it is therefore a great kindness 

 on his part to allow me to show them here in 

 London. 



First of all, we have the cliff of Permian strata 

 on the banks of the Dwina (Fig. 153), from 



Fig. 153. — View of one of the dark patches in the cHffs of the 

 river Dwina (the Northern of that name), where nodules 

 containing the skeletons of extinct reptiles are found. 



which and from another similar spot the remains 

 were extracted. At this point, where the colour 

 is dark in the photograph, there is a peculiar 

 " pocket " or accumulation of sandy matter 

 with large hard nodules embedded in it. These 

 nodules are removed and broken up for mending 



213 



