THE N I AG ARAN FORMATIONS OF WESTERN OHIO 355 



Thickness 



Total 

 Thickness 



No. Feet Inches Feet Inches 



overlie it. It contains some calcite crystals and 



a Brachiopod shell similar to a small Pentam- 



erus 1 10 4 2 



2. Layer similar in lithologic characters to the 



superjacent one 6| 2 4 



1. Mottled zone. — Massive layer of drab color, 



mottled with light-gray spots and blotches. 



Compact rock and harder than layers above. 



This was the lowest exposed layer near the 



northern end at the time the quarry was 



studied in July, 1914 1 9 1 9 



The Springfield dolomite in this quarry is believed to comprise 

 the zones numbered 2 to 10, inclusive, which have a total thickness 

 of 13 feet 7! inches. The same formation in the Jackson quarry 

 is 13 feet 3 inches thick, which shows a close agreement in these 

 two sections, since there is a difference of but \\ inches in the thick- 

 ness of the Springfield formation in the two quarries. 



Section near Lewisburg.— About 20 miles southwest of Coving- 

 ton is the large quarry of the Lewisburg Stone Co., which is rather 

 more than a mile northwest of the station at Lewisburg, Preble 

 County, and located on the southern bank of Twin Creek. This 

 quarry and the bank of Twin Creek below the crusher furnish an 

 important section, since almost the complete series of rocks from 

 the upper part of the Brassfield limestone into the lower part of 

 the Cedarville dolomite are admirably shown. The western wall 

 of the quarry extends higher stratigraphically than the southern 

 wall, but with the exception of the extreme top of the section it 

 was the southern wall of the quarry toward the western end that 

 was measured. 



Section at the Lewisburg Stone Co. Quarry 



Thxckness ThWss 



No. Feet Inches Feet Inches 



20. Cedarville dolomite. — Light-gray, weathering to 

 a dark-gray, porous reck with the lithologic 

 appearance of typical Cedarville. At the time 

 the quarry was studied, on account of the shat- 

 tered condition of the wall, due to extensive 

 blasting, it was difficult to decide where the line 



