4 FLORA OP LOWER COAL MEASURES OF MISSOURL 



STRATIGRAPHY OF THE PLAJSTT-BEAEIXG TEREA]ST:S. 



All the plants treated in tlie following pages were derived from the 

 Lower Coal Measures of Missouri as defined by the earlier State surveys. 

 More recently the terms Des Moines series^ and Lower Coal Measures have 

 been applied to the combined Lower and Middle Coal Measures of the 

 earlier nomenclature. The present collections are mostly restricted to the 

 lower di-snsion or to the Cherokee as defined b)' Haworth and Kirk,^ and 

 used by the Missouri geologists. I employ the term Lower Coal Measm-es 

 in its original American sense, as it has long been in general use in the 

 northern bituminous basins. It is, under the circumstances, all the more 

 appropriate since the flora in hand is in fact representative of that division 

 of the Carboniferous resting on the Pottsville series in the northern and 

 northeastern coal fields. At the same time, it must be borne in mind that 

 the title refers only to the American application of the term, as commonly 

 used in the reports of the earlier geologists of the Northern States. 



It must be remembered that in Missouri, as in Iowa, the Coal Measures 

 (Mesocarboniferous) rest on the eroded surface of the Lower Carbonifer- 

 ous (Eocarboniferous). Along a portion of the margin of the field the floor 

 of the Mesocarboniferous consists, as is largely the case in the latter State,' 

 of the deeply cut surface of the St. Louis limestone or other di\'isions of 

 the Mississippian. In other portions the Coal Measures rest unconformably 

 on other di-\dsions of the Eocarboniferous, on the Devonian, the Upper 

 Silurian, or the Lower Silurian. 



The probable epeirogenic movements and the consequent changes of 

 both the level and the attitude of the continent in the region bordering the 

 o-reat coal field have been fully discussed by Winslow* and by Iveyes, 

 the latter of whom has also given a profile diagram of the oscillations of the 

 shore line in the Missouri-Iowa region during Eocarboniferous and Meso- 

 carboniferous time.^ The deposition of the lower portion of the Mesocar- 



'Keyes, Am. Geologist, vol. xviii, 1896, p. 23; Rept. Geol. Surv. Iowa, vol. i, 1893, p. 85; Monthly 

 Review, Iowa Weather Service, vol. iv, 1893, p. 3. 



- Kans. Univ. Quarterly, vol. ii, 1894, p. 105. Univ. Geol. Surv. Kans., vol. i, 1896, p. 150 



' Am. Geologist, vol. xii, 1893, p. 99. Hall, Am. Jour. Sci., vol. xxvil, 1857, p. 197. 



■'The Missouri Coal Measures and the conditions of their deposition : Bull. Geol. Soc. Am., vol. iii, 

 1892, pp. 109-121. See also Am. Geologist, vol. xv, pp. 87-89, and Prelim. Rept. on Coal : Geol. Surv. Mo., 

 1891, p. 19. 



■•Am. Geologist, vol. xli, 1893, p. 100. 



