430 CHARLES S. PROSSER 



of this zone occur in the Marcellus shale and later Devonian forma- 

 tions of New York, instead of the Onondaga limestone, and therefore 

 supports Whitfield's conclusion that it is the "equivalent of the 

 Marcellus shale of New York." 1 



DEEP RUN SECTION 



In the southern part of Delaware County a number of small 

 streams entering the Olentangy River afford good sections of a part 

 or all of the Delaware limestone. One of the best of these is the 

 small stream known as Deep Run, on the Matthews farm on the 

 eastern side of the river, which enters the river at the ford opposite 

 the Armstrong farm. The stream is rather more than three-fourths 

 of a mile north of the Powell road and bridge, about one-half mile 

 south of the Orange road and bridge, and may be readily reached 

 from Stop No. 42 on the Columbus, Delaware & Marion Electric 

 Railway. 



Thickness Total Thick- 



No. (Feet) ness (Feet) 



10. Ohio 'shale. — Mainly black, thin, somewhat gritty 95 I 75i-+ 



shale, but there are thin layers of greenish or mottled 

 shale. The barometer indicates that 95 feet is shown, 

 in the lower 40 feet of which are numerous concretions, 

 some of which are of large size. 

 9. Olentangy shale. — Mainly greenish shale, the top of 25+ 80J4- 



which is sharply shown in a small fall in the stream, 

 and a little below in a steep bank of shale on its north- 

 ern side, where 10J feet of Olentangy shale is shown. 

 Calcareous concretions occur in the upper part of this 

 shale, which are well shown in the bank just mentioned, 

 where one layer occurs about 3^ feet below its top, 

 another 7J feet below, and a third 9 feet below, of 

 impure calcareous material which nearly forms a layer. 

 These concretions contain plenty of marcasite or iron 

 pyrites. There is also abrownish layer of shale a foot 

 or so above the lower line of concretions. The meas- 

 urement is by hand level from the top of the limestone 

 over the covered valley and up the bank to the north- 

 east to the base of the Ohio shale, as shown in a small 

 lateral ravine; but there is a heavy dip in the same 

 direction, so that the measurement of 25 feet is less 

 than the true thickness, probably to the extent of 5 

 feet. 

 1 Ibid, p. 298. 



