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



From Lower Outcrop nearly due east to Indian Creek the 

 Upper Mercer dips 1 foot in oh miles. The Howenstein dips in 

 the same direction from Bingham Outcrop to Indian Creek 

 8 feet in nearly 7 miles. The Lower Mercer rises from Club 

 Lake to Neff Run in a direction 7h miles east and 1 mile north 

 6 feet in 7^ miles. It is seen at once that the strata lie almost 

 horizontally from east to west in the center of the county. 



From Neff Run to Lanterman Outcrop more north than east 

 the Lower Mercer falls 19 feet in r>h miles, whereas it would be 

 expected to rise judging from its position to the west of Neff Run. 

 From the same run to Davis well very nearly northeast the Upper 

 Mercer lies horizontally having an elevation of 1050 at each place 

 and 3^ miles between. From Neff Run to Greenhouse Hill 

 exactly northeast the Howenstein falls 2 feet in -i miles. The 

 average for the three strata is seen to be about a 2-foot fall per 

 mile. In a direction so much north of east a rise of several feet 

 per mile would be expected. 



From the Beardsley Outcrop to Neff Run in a direction IJ 

 miles south of east the Lower Mercer rises 8 feet in 4 miles. 

 Further comment on the dip and position of the strata in central 

 Mahoning County will be made in connection with the Yellow 

 Creek and Lowellville sections. 



YELLOW CREEK. 



This stream is a tributary of Mahoning River and flows north- 

 ward nearly parallel to Mill Creek half way between the latter 

 and the state line. It has a fall of about 210 feet in 5 miles and 

 its rapid current has cut a deep gorge from the village of Poland 

 to its mouth at StrUthers. Accordingly unusually good expo- 

 sures of the Potsville formation are afforded. 



Poland Outcrops. At the village of Poland two outcrops of 

 limestone occur. The first is seen on the north side just below the 

 cemetery forming a conspicuous ledge and water fall in Yellow 

 Creek. It is the Lower Mercer and lies at 990 feet above sea. 

 The stratum presents here that peculiarity of two layers noted 

 elsewhere. The upper layer measures 2 feet, 3 inches and the 

 lower 7 inches. Resting directly upon the heavy bed is a 2-inch 

 very impure layer of limestone of cone-in-cone structure which 

 breaks easily and shows this peculiar structure quite admirably. 

 The heavy bed is bluish gray, tough, fossiliferous, and sparkles 

 with crinoid stems and calcite crystals. The limestone is directly 

 underlain by black carbonaceous shale which is extremely fossili- 

 ferous. vSeventeen feet of yellowish-gray flaggy sandstone over- 

 lies this limestone at this point. 



One and one-half miles from the Mahoning River the City of 

 Youngstown has built a dam on Yellow Creek, the head water of 

 which is found a few hundred yards below the above outcrop. 



