EXPERIMENTS OP SIR JAMES HALL. 



141 



ARCHED STEATA. They sometimes form an .arch, as 

 in the Malvern hills (fig. 64). 



FIG. 64. 



CONTORTED STRATA. Occasionally they are contorted, as 

 on the banks of the Wye (fig. 65), and near May Hill. 



FIG. 65. 



EXPERIMENTS or SIR JAMES HALL. Such contortions 

 were shown by Sir James Hall, by a simple experiment, to 

 have arisen from lateral pressure, attended with some degree 

 of resistance, both above and beneath. He took various 

 pieces of cloth some linen, some woollen and placing 

 them horizontally on a table, c, covered them by a weight, a, 

 acting horizontally on the pieces of cloth. 



