ISLANDS. 461 



Carrington and Hat Islands evidently form part of the same uplift witli 

 Stansbury Island, and belong, like it, to the Lower Coal-Measure group. 

 Associated with the limestones of Carrington Island is a considerable devel- 

 opment of finely-laminated argillaceous slates, which contain little cubes of 

 iron pyrites and some coarse conglomerates. The mass of Hat Island is 

 principally made up of these slates and conglomerates. Between Hat Island 

 and Fremont's Island is, as has been seen, the deepest portion of the lake, 

 the bottom being over forty feet below its present surface. 



