ii8 The Ohio Naturalist. [Vol. X, No. 5, 



measures 3 feet 6 inches. The rich bed of iron ore above it was 

 formerly mined and used in the manufacture of paint. 



This limestone is being burned for fertilizer on the John Fitch 

 farm near West Austintown. 



McMahon Outcrop. About Ij miles southeast of the Ripple 

 outcrop an exposure of limestone occurs on McMahon Run and 

 on the farm of Ambrose McMahon. The full thickness is not 

 now exposed but reported to be 2 feet or more in a coal shaft at 

 this point. Drillings close around gave a thickness of 2| to 3 

 feet. In one hole reported by Mr. McMahon a 2-foot coal was 

 penetrated 10 feet above the limestone. As seen in the run the 

 limestone lies at about 1040. The coal at the shaft lies 25 feet 

 below the limestone or at 1015, but in one of the drill holes at 20 

 feet below that stratum. The limestone is overlain by a rich 

 bed of iron ore as at the Ripple outcrop and would seem from all 

 the data to be the Lower Mercer although 12 feet higher than at 

 previous outcrop. Undulation will easily account for this 

 difference. The 2 foot coal above it would seem to be the coal 

 belonging to the Upper Mercer but no trace of this limestone or 

 its coal is seen in the run above the shaft where the next 35 feet 

 of strata are exposed. 



Smith Corners. At Smith Corners about one mile a b"ttle 

 south of east from the McMahon outcrop William Gardner pen- 

 etrated a limestone of about 18 inches thickness at 1090 above 

 sea. The dip toward the southeast in eastern Mahoning County 

 is only about 5 feet per mile, the interval therefore of 55 feet 

 indicates rather clearly that this is the Howenstein limestone. 

 The McMahon outcrop, Smith Corners and Poland are nearly in 

 line and the matter 'of dip in that direction will be considered 

 further under Poland outcrops. 



MILL CREEK AND TRIBUTARIES. 



This stream empties into the Mahoning River at Youngstown 

 after crossing the eastern end of Mahoning County from south 

 to north. Its bed for more than 7 miles from its mouth lies 

 below the horizon of the Lower Mercer limestone, and the scanty 

 outcrops of the limestones, therefore, are found on its tributaries. 



Facodi Outcrop. In the first ravine to the east above the fall 

 at the old Lanterman Mill on Mill Creek, the Lower Mercer is 

 first seen on the land of Una Facodi at 1010 feet above sea. The 

 exposure is poor and the thickness not seen. It is underlain by 

 gray sandy shale and flaggy sandstone down to Mill Creek. This 

 sandstone is the Upper Massillon and it constitutes the rock 

 walls of Mill Creek gorge. 



Lanterman Outcrop. About one-fourth mile south of the 

 Facodi outcrop and on the German Lanterman farm the Lower 

 Mercer outcrops in a ravine which crosses the north and south 



