THE NIAGARAN FORMATIONS OF WESTERN OHIO 341 



Thickness 



Total 

 Thickness 

 No. Feet Inches Feet Inches 



8. Zone of rather thin layers of light-gray to 

 bluish-gray dolomite, with shaly to shale part- 

 ings 1 4 12 i| 



7. Osgood beds. — Zone of rather dark -gray shale 

 which weathers to a bluish-gray color and is 

 rather calcareous. Conspicuous zone on quarry 



wall. 



32 10 oi 



6. Dayton limestone. — Massive zone at top of Day- 

 ton limestone which splits into at least 3 layers, 

 which, in descending order, are respectively 9 

 to 10,3, and 1 1 to 1 2 inches thick . It is a light- 

 to bluish-gray, compact limestone : . . 2± o 7 7 J 



5. Light- to bluish-gray limestone forming massive 

 zone on northern wall. It splits, however, into 

 3 layers, which, in descending order, are re- 

 spectively 11, 7, and 8 inches thick 2 2 5 ~j\ 



4. Light-gray layer on weathered face from 12 to 

 14 inches thick, which will split into 2 or 3 

 layers.... 1 1 ± 3 5 f 



3. Layer similar to those below it 10 2 4% 



2. Bluish-gray, compact layer, 7 to 8 inches 



thick 7§± 1 6J 



1. Bluish-gray, compact rock, containing large 

 masses of calcite. Bottom of exposed rock in 

 quarry 11 • n 



In the foregoing section the shale zone (No. 7) which separates 

 the Dayton limestone from the Laurel limestone is beautifully 

 shown on the quarry wall. This layer of shale was recognized in 

 various sections in Miami and Preble counties and is a very impor- 

 tant aid in identifying the formations of these counties and corre- 

 lating them with those of southeastern Indiana. 



At the western end of the almost continuous line of quarries on 

 the northern side of Ludlow Creek is the Maxwell quarry, the 

 upper part of which carries the general section along Ludlow Creek 

 stratigraphically higher than those already described. The follow- 

 ing section of this quarry was measured at its western end to the 

 west of the J. J. Wagner brick house: 



