32S TRANS. ST. I.OUIS ACAD. SCIENCE. 



Thickness Total 

 of Stratum. Depth. 

 iS. Light gray limestone, pure, probably massive 



or thick-bedded, with conchoidal fracture 2S' 213' 



19. Light gray sub-crystalline limestone intermixed 

 with dark gray shale 



20. Light gray slightly calcareous shale and clay... 



21. Dark gray slightly calcareous clay 



22. Calcareous gray shale 



23. Light gray cherty limestone 



24. Light gray limestone, dark gray calcareous 

 shale, and chert 



25. Light gray cherty limestone 



26. Bluish gray calcareous shale 



27. Light gray cherty limestone and dark gray cal- 

 careous shale 10' 6" 335' 6" 



28. Light gray and dark gray nodular calcareous 



shale 39'6 375' 



29. Light gray siliceous limestone and chert 21' 396 



30. Light buff pulverulent rock containing beautiful 

 crystals of carbonate of lime and carbonate of 

 iron, and leaving a considerable residue (proba- 

 bly siliceous and magnesian) after digestion in 



acid 14' 410' 



31. Dark gray arenaceous shale, light gray calcare- 

 ous shale, and crystals of calcite 72' 4S2' 



32. Light gray arenaceous and calcareous shale 



with light buff powder like 30 27' 509' 



33. Blue sparry limestone with fossil markings 23' 532' 



34. Shaly blue limestone 43' 575' 



35. Light gray and dark blue shaly limestone 60' 635' 



36. Blue limestone 17' 652' 



37. Light blue sparry limestone 112' 764' 



38- Light blue cherty and arenaceous limestone 36' 800' 



39. Gray sparry limestone and fine fissile blue shale 95' 895' 



40. Massive blue shale or indurated clay 100' 995' 



41. Fine ca'careous sand 5' 1000' 



T/ic General Section. — It should be mentioned that while 

 only the more important of the exposures observed in Macon 

 county are recorded in the foregoing paragraphs, a large number 

 of outcrops of single ledges or beds were examined and found to 

 afford material aid in tracing and correlating the strata ; and it 

 should be added that many strata — e.g. the clinking limestone, 

 the brown dolomite of Claybank creek, the Proditctiis limestone, 

 the nodular black shale, etc. — exhibit numberless minute but per- 



