SPORE DISTRIBUTION — McLEANSHORO 



95 



more or less typical of those assemblages in 

 the upper coals of the Carbondale Group 

 but differs in some respects and may prove 

 to be distinguishable. 



The only previous comprehensive study 

 of megaspore occurrences throughout the 

 Pennsylvania]! of North America is that by 

 Cross (1947) on the spore floras of West 

 Virginia and Kentucky. Using Cross' chart 

 (1947, fig. 2, p. 287), showing spore distri- 

 bution for West Virginia and Kentucky, 

 some general comparisons can be made 

 with the megaspore occurrences known 

 from Illinois coals. 



Cross found smooth aphanozonate spores 

 (in particular those of Triletes glabratus, 

 s. 1.) in the Lower War Eagle Coal and 

 a few coals in the upper part of the Potts- 

 ville Series, but they seem to occur with 

 some regularity, from coal to coal, in and 

 above the Upper Freeport Coal. These oc- 

 currences parallel the marked abundance 

 of these spores in the upper part of the Car- 

 bondale Group and in the McLeansboro 

 Group of Illinois. 



Spinose lageniculate spores apparently 

 are found in some coals of the Pottsville 

 Series but are not known to occur above the 

 No. 5 Block Coal in the lower part of the 

 Allegheny Series. In Illinois, distinctly 

 spinose lageniculate spores are unknown 

 above the Tarter Coal of the Tradewater 

 Group. Smooth lageniculate spores of the 

 Triletes rugosus (s. 1.) type occur with 

 regularity in the upper coals of the Potts- 

 ville Series. This also may parallel their 

 sudden occurrence in, and more or less 

 common occurrence above, the coals of the 

 upper part of the Tradewater Group. 

 Spores similar to those described as T. levis 

 and questionably referred in this report to 

 the section Lagenicula were reported by 

 Cross from the Waynesburg Coal in the up- 

 per part of the Monongahela Series. Dijk- 



stra (1958) reported similar spores from 

 the Lawrence Shale of Kansas. These 

 spores are typical of the upper portion of 

 the McLeansboro Group in Illinois. 



Zonate megaspores are not known with 

 certainty above the No. 5 Block Coal; their 

 most common occurrences appear to be re- 

 stricted to the Pottsville Series. These 

 spores are not known from Illinois coals 

 above the top of the Tradewater Group. 



Triangulate and auriculate megaspores 

 occur sporadically from the Cedar Grove 

 Coal in the Pottsville Series throughout the 

 Pennsylvanian of West Virginia and Ken- 

 tucky. These megaspores also occur, more 

 or less, throughout the Pennsylvanian of 

 Illinois. 



Cross also noted the presence of spores 

 of genera other than Triletes. He did not 

 record the presence of Cystosporites above 

 the Pittsburgh Coal at the base of the Mo- 

 nongahela Series. The genus occurs through 

 upper Mississippian and most of the Penn- 

 sylvanian of Illinois, but is not represented 

 in the upper portion of the McLeansboro 

 Group. Monoletes is reported only from 

 the Buffalo Creek and Coalburg Coals of 

 the Pottsville Series although it is repre- 

 sented in most of the coals in the Pennsyl- 

 vanian of Illinois. Spores, probably of 

 Spencerisporites , are noted as occurring up 

 to the lower part of the Allegheny Series. 

 The genus is represented sporadically 

 throughout the Illinois Pennsylvanian. 



More detailed comparisons and conclu- 

 sions are left to the reader. These will nec- 

 essarily vary depending on each individ- 

 ual's opinion on the circumscription of the 

 various taxa. As more studies on both small 

 and large spores are completed, a clearer 

 total picture of floral elements and their 

 areal and stratigraphic distribution should 

 emerge. 



