Conglomerates of Sauk County, Wisconsin. 95 
phlet did not fallinto my hands until after my own investigations 
were entirely completed. In the first volume of his e 
ort, Mr. Hall again mentions the quartzites, but still more 
rock shows readily the reason for its not becoming saline. 
The great exposures of cliff at this locality, and the deep rock 
cuttings on the newly-opened railroad, afford most excellent 
Opportunities for study. The change of direction, too, of the 
valley, gives facilities for approaching the rocks from different 
sides, not elsewhere easily obtainable. 
