598 



A. W. GRABAU TYPES OF SEDIMENTARY OVERLAP 



by Ulrich with the base of the Tullahoma formation of middle Ten- 

 nessee. That the hiatus recorded or believed to exist between the Syla- 

 more and Saint Joe is equivalent to the whole Kinderhook may be 

 doubted. The evidence on which to base the reference of the Sylamore 

 to the Devonic is altogether too meager; it is far more likely that this 

 formation represents a basal bed of Kinderhook age, possibly in part 

 continental, and that it is in general equivalent to the Noel shale, as held 

 by earlier writers. 



Whatever the age of the Sylamore, the relationship of the Black shale 

 (Eureka or Noel) to the overlying and underlying formations is clear. 

 It represents a basal bed of an advancing sea, and progressively rises in 

 the scale southward from middle Kinderhook to uppermost Kinderhook 

 or lowest Burlington. That this basal bed is such a fine grained rock 

 can only be explained by the assumption that the land was very low, and 

 that the residual soil covering it was clay mixed with much carbonaceous 

 material. In other words, the Noel shale can only represent the re- 



^-- 



Ik - v« 



)1 -= )!'■ — . 



•*■ )f> -J ^ 



=T\ 



—^-l( -==■ 1 11 - ,<?/ J~n<> £, 77? esto r?e (R»-/ST*r./-n» ) Ik - V, ~- ft. 



Figure 4. — Diagrammatic View of the Relationship of the Black Shale of southern 

 Missouri and northern Arkansas to the overlying Formations. 



worked residual soil of an old peneplain surface which was slowly sub- 

 merged beneath the advancing Mississippian sea. Taken in connection 

 with the position of the Black shale at the base of the Louisiana lime- 

 stone in northeastern Missouri, we see that the transgression went on 

 through the entire Kinderhook. 



There seems to be no valid reason for considering that the Black shale 

 of northeastern Missouri had a different origin from that of south- 

 western Missouri; and if the Noel shale represents the basal bed of a 

 transgressing sea in southern Missouri and northern Arkansas, there is 

 no reason for regarding the Louisiana Black shale as having a different 

 meaning. A significant fact in this connection is the similarity in the 

 general lithic character of the section in northeastern and southwestern 

 Missouri. In the northwestern section the shale is succeeded by the 

 compact Louisiana limestone; this by the Hannibal sandstone or vermic- 



