3. CENTRE TOWNSHIP. F 2 . 179 



sandstone. Here its harder beds may be seen cropping ont 

 in the streets with an almost vertical dip. 



The road to Newport lies for several hundred feet ex- 

 actly on the southern edge of the variegated shale, and 

 about half a mile east of the town is a low cutting which 

 displays the alternations of color and hardness very dis- 

 tinctly. Farther east it lies south of the road bed but may 

 easily be traced where the fields have been recently plowed, 

 through the farms nearly to the township line on the road 

 to Baileysburg. 



This red and green shale lies in the upper portion of what 

 was called, in the Report of the First Survey, No. V, and 

 is the equivalent of the Onondaga salt group of New York, 

 but to my knowledge has never yielded either salt or gyp- 

 sum (plaster) in this county. It represents the middle por- 

 tion of the group in New York which lies under the gypsum 

 and salt bearing strata. (See Chapter III, page 53. 



The Onondaga gray shales. (No. V.) 



These beds make no conspicuous show in the township. 

 They are apparently 200-250 feet thick but no measurement 

 can be obtained. They form, with the variegated shales 

 just described, the south slope of Limestone ridge, and ex- 

 tend under part of the flat land in the valley between the 

 Oriskany and the Bloomfield sandstone, the latter being the 

 upper layer of the variegated shale which forms a low ridge 

 along the valley. 



The Lewistown limestone. {Lower Helderberg, No. VI.) 



The second geological formation in Centre township is 

 the Lewistown limestone, so called from its great develop- 

 ment near Lewistown, in Mifflin county. 



This is the bed from which all the lime made in the town- 

 ship is obtained. It corresponds, as has been determined 

 from its fossils, to the water-lime division of the Lower 

 Helderberg limestone of New York. 



It consists of a hard, solid, thick-bedded limestone, with 

 a thickness near New Bloomtield of about 60-70 feet, from 

 which it does not largely differ anywhere in the township. 



