EXPOSURE IN THE KEUPER CLAYS AND MARLS. 219 



on the Burton Road near the top of Argyle Street, and in 

 Liltleover Lane. The phenomenon is by no means uncommon 

 on the slope of a hill, where it may be referred to the action of 

 debris sliding down the hill, but that explanation cannot hold 

 here, as the ground is for several hundred yards around fairly 

 level. Taking into account the neighbourhood of the glacial 

 deposits referred to above, and the position of the beds, this 

 seems to be the best — indeed, the only explanation of ihe 

 phenomenon. There are several thick beds of marl in the pit, of 

 considerable hardness, many of them exhibiting ripple-marks 

 upon their surfaces. In some of them also are to be seen 

 sharply-cut cubical indentations, as though a dice had been driven 

 into the rock when in a plastic condition. These are, doubtless, 

 cavities left by cubical crystals of rock salt, and are by no means 

 uncommon in these salt-bearing strata. These and the ripple- 

 marks indicate the shallow-water character of the deposits. The 

 crystals of rock salt would be dissolved by the returning water, 

 which would deposit sedimentary material in them. Doubtless, 

 a search would lead to the finding of these pseudomorphs after 

 salt. I have only seen the casts. 



Considering the nature of the beds of rock salt and gypsum 

 occurring in these strata, it is by no means unhkely that this 

 fault is due to subsidence. The exposure is certainly an 

 interesting one, and lies at our very doors. 



