APPENDIX. 



Section for Arkansas — Continued. 



561 



Names of Formations. 



Thickness 

 in Feet. 



Characteristics. 





Polk Bayou limestone. 



75 



Highly crystalline limestone in massive layers; 

 light gray to chocolate-brown. 



.2 

 "S 



"i ^ 



Izard limestone. 



285 



Fine-grained; compact, non-fossiliferous, even- 

 ly bedded; mainly dark blue, but varies to 

 buff, light gray, and almost black. 



o 



Saccharoidal sand- 

 stone. 



125 



Friable; usually white, but often brown; some- 

 limes quartzitic. 





Calciferous or Magne- 

 sian limestone. 



1625 



Brownish 7 gray arenaceous dolomite, few fos- 

 sils. 



