196 GEOLOGY OF OHIO. 



taneous flow of carbureted hydrogen gas from the Huron shale has been 

 extensively utilized. Fredonia was for many years exclusively, and still 

 is partially, lighted by natural gas, and at Erie wells sunk for the pur- 

 pose are supplying combustible gas which is being successfully applied 

 to the heating and lighting of residences and manufacturing establish- 

 ments. 



The gypsum and hydraulic lime of the Waterlime and Salina groups 

 should, perhaps, be enumerated among the mineral resources of Erie 

 county, as, though not found upon the surface, they lie not far below. 

 The quantity and accessibility of these materials are, however, yet so 

 much in doubt that no one would be justified in anticipating a great 

 increase in the wealth of the county from this source. 



In concluding this report, it affords me pleasure to acknowledge my 

 obligations to Dr. A. H. Agard, Mr. L. P. Wheelock, and Hon. D. C. 

 Richmond, for valuable assistance rendered in my explorations of the 

 county. 



