LOWER SILURIAN SYSTEM OF EASTERN MONTGOMERY CO. 45 1 



hundred feet up the steep hillside. The lowest exposure is just 

 beneath the arch of the West Shore railroad bridge where crumbling 

 shale is exposed in the creek bed. Beginning at this point a sec- 

 tion was measured by means of tape and Locke level. 



2 1 Rotterdam section 



P Near the railroad arch in the bottom of the 

 creek 8 feet of very thin^ fragile, dark grayish to 

 bluish black, argillaceous shales with occasional 

 very thin sandy layers, one near the middle of the 

 stratum being about i inch thick. 8'= 8' 



P Heavy, compact sandstone of grayish to 

 greenish blue color, weathering gray to brown. io'= i8' 



P Mainly grayish, friable shales with thin layers 

 of sandstone. 



I* Heavy sandstone with intercalated shale. 



I^ Dark crumbling shale. 



I^ Shale with mainly thin, but some heavy layers 

 of sandstone. 



I*^ Heavy stratum of sandstone. 



I^ Shales with some thin layers of sandstone. 



I^ Thiok to thin and broken layers of sandstone. 



1^0 Fine shale. 



I^^ Thin broken sandstone with crumbling shale. 



112 Shale. 



V^ Thin sandstone and shale. Base of high 

 waterfall. 



P^ Thin friable blackish shale by excavation of 

 which from beneath the sandstone above^ the fall 

 has been formed. 



1^5 Two layers of massive sandstone over which 

 the water falls. 



I^^ Thin sandstone layers. 



I^*^ Clear dark shale. 



I^ Apparently heavy bedded sandstone weather- 

 ing to thin often lenticular divisions. 



P^ Shales and thin sandstones. 



120 Medium thick layers of sandstone with mas- 

 sive 2 foot layer at base and some thin beds of 

 shale, and shaly partings. 39'== 270' 



12'= 



30' 



6'= 



36' 



8'= 



44' 



37'= 



81' 



4'= 



85' 



15'= 



100' 



I0'= 



no' 



5'= 



"5' 



45'= 



160' 



5'= 



165' 



5'=' 



i 

 170' 



12'= 



182' 



8'= 



190' 



2'= 



192' 



4'= 



196' 



25'= 



221' 



I0'= 



231' 



