Prosser — Stratigraphic Position of Hillsboro Sandstone. 441 



Total 

 Thickness Thickness 

 No. Ft. In. Ft. In. 



base of the outcrop of the Ohio shale 

 on the road is 4 feet 10 inches. From 

 the top of the same limestone to out- 

 crops of Ohio shale in gullys to the 

 northwest is 10 feet by the barometer. 

 On the surface above the top of this 

 quarry are loose blocks of white, fine- 

 grained, quartz sandstone, similar lith- 

 ologically to the upper layer of sand- 

 stone in the road gutter. 4 10 35 2 



5. Monroe dolomite. — Compact, light to 

 bluish-gray, hard rock, which is some- 

 what porous, and contains some fossils. 

 The upper part of this zone is shown 

 in the highest or third quarry 8 10 30 4 



4. Rather massive layer, somewhat granular, 

 rather porous and effervescence fairly 

 strong in cold commercial HC1. This 

 layer forms the top of the middle or 

 second quarry and is rather similar lith- 

 ologically to the porous 11-inch stratum 

 (No. 7) in the road gutter 2 6 21 6 



3. Drab or brownish to gray rock weather- 

 ing to a very light gray which is fairly 

 compact, lithologically like the Mon- 

 roe dolomite, and contains a few fossils. 

 In the floor of the quarry are irregu- 

 lar dome-like elevations similar to 

 masses that are not infrequently found 

 in the Monroe. The rock has been 

 quarried and crushed to some extent 

 for highways ... 6 6 19 



2. Covered interval 5 5 12 6 



1. Cedarville dolomite. — Porous, buff to 

 gray rock which effervesces strongly in 

 cold commercial HC1. At the bottom 

 of this lowest or third quarry is a 

 heavy layer, and this zone has the lith- 

 ologic appearance of the Cedarville ; ' 

 although perhaps not all of the upper 

 part of this quarry belongs in the 

 Cedarville. No fossils were found 1 \ 7 1 



Across the gully to the east of the middle quarry in the 

 above section are loose blocks of light gray, quartz sandstone 

 which are evidently from a broken-down stratum of the Hills- 

 boro sandstone. These loose sandstone blocks occur in a ver- 

 tical interval of 6 feet and the lowest ones, as leveled across the 



