NOTES ON TEE MiISSISSIPPIAN CHERD OF THE 
Sf. LOUIS AREA 
DONALD C. BARTON 
Cambridge, Massachusetts 
The origin of chert is a question which is still open to discussion. 
Although several of the chert series of Europe have been studied 
somewhat in detail by a number of geologists, among the more 
important Hull and Hardman, Hinde, Sollas, Renard, and Cayeux, 
the conclusions reached with regard to the origin of chert have 
been considerably at variance. In this country Lawson and 
Palache seem to have demonstrated the organic (radiolarian) origin 
of certain Californian cherts. ‘The Missouri cherts, chiefly Missis- 
sippian, and some of the closely associated cherts of neighboring 
states have been studied, although not in detail, by Shepard, Ball 
and Smith, and Van Tuyl, and, in thin section only, by Hovey. 
The conclusions as to the origin of the chert have not been in agree- 
ment. ‘The present paper presents the results of a detailed study 
of the Mississippian cherts of the St. Louis area both in the field and 
in thin sections. 
OCCURRENCE OF THE MISSISSIPPIAN CHERT OF THE 
ST. LOUIS AREA 
The Mississippian chert of the St. Louis area is found in the 
St. Louis and in the Burlington-Keokuk limestones, to a slight 
extent in the Warsaw shales, and in very rare, small patches in the 
1 E. Hulland E. T. Hardman, Trans. Royal Soc., Dublin, I (1878),71. G.J. Hinde, 
Geol. Mag. (III), IV (1887), 435-46. W.J.Sollas, Am. Mag. Nat. Hist. (5), VI (1880); 
VII (1881); Proc. Roy. Soc., Dublin, VI (1887), Part 11. A. F. Renard, Bull. Acad. 
Roy. Belgique (2), XLVI (1878), 471. L. Cayeux, Ass. frang. pour Pavanc. de Sci. 
(Carthage, 1906), pp. 220-93. A.C. Lawson and C. Palache, Bull. Geol. Dept. U. of 
Cal., IL (1902), 354-65. E.M. Shepard, U.S. Geol. Surv., W.S. Paper 195 (1907), 
p.19. T.M. Van Tuyl, Proc. Iowa Acad. of Sci., XIX (1912),173-74. E. O. Hovey, 
Mo. Geol. Surv., VII, Part II (1894), pp. 727-39. 
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