Tarr — Origin of the Chert in the Burlington Limestone. 419 



Section of Burlington limestone^ Greene Co.^ Missouri. 

 E. M. Shepard, Geol. Sur. Mo., vol. xii, pp. 100-123, 1898. 



Upper Burlington 



Shaly limestone: thin-bedded, compact, 

 rarely oolitic, interbedded with layers of chert 

 which are usually fossiliferous. The lime- 

 stone is very fossiliferous, coarse-grained and 

 varies from white to gray in color. Middle 

 beds are coarse-grained, crystalline, soft, gray 

 to white in color, have many nodules of chert, 

 are stylolitic, and pass downward into a shaly, 

 coarsed-grained limestone ._ _- 200 ft. 



Low^er Burlington 



Limestone and chert: consists mainly of 

 brownish yellow, blue, or slate-colored beds; 

 fine to medium-grained; contains some fossil- 

 iferous bands; middle portion thin-bedded; 

 top is mainly yellowish-white chert; much 

 nodular chert and many lenticular layers of 

 chert in the lower part . _ 70 ft. 



Sectio7i of the Burlington limestone, Calhoun Co., Missouri. 

 C. F. Marbut, Geol. Sur. Mo., vol. xii, p. 161, 1898. 

 Upper Burlington 



Gray or white, coarse-grained encrinital 

 limestones in rather massive beds, with chert 

 nodules scattered throughout; very fossilifer- 

 ous _ _ 80 ft. 



Lower Burlington 



Limestone: rather fine-grained; drab; some- 

 what earthy; has many crinoid stems and much 

 chert, the latter occurring as masses through- 

 out the limestone and as thin layers alternat- 

 ing with thin layers of limestone 30 ft. 



^Section of the Burlington formation in Pike Co., Missouri.- 

 R R. Rowley, Geol. Sur. Mo , vol. viii, p. 36, 1917. 



Upper Burlington 



Thin bands of brown and yellow limestone 



and chert .. "_. 20 ft. 



Lower Burlington 



Blue limestone _, 4 ft. 



White limestone with very little 

 chert - . _ _ _ 10-14 ft. 



White and brow^n layers of lime- 

 stone with considerable chert in some 

 beds _ _ 15-30 ft. 



Limestone 5- 8 ft. 50 ft. 



