Burlington Limestone in Northeastern Missouri. 449 



feet. 5 and 6 are probably Devonian, equivalent to the 

 " black shale " of adjoining States. Number 7 is a thin seam 

 2 to 4 inches in thickness and highly fossiliferous. With few 

 exceptions the " Lithographic " fossils come from this layer. 

 It probably belongs more properly with beds 5 to 6. Appar- 

 ently the organic remains are nearly all identical with forms 

 from the Hamilton rocks farther northward. Should the 

 union of this thin, highly fossiliferous seam to the underlying 

 shales be more in harmony with the real relation of the faunas 

 of the respective beds, as now seems likely, than with the 

 faunas above, it would remove to a great extent the present 

 Devonian facies from the Lithographic (Louisiana) limestone. 

 8 is the Louisiana limestone, a compact rather thinly bedded 

 rock, breaking with a conchoidal fracture. It is very poor in 

 fossils. Numbers 9 and 10 are the Hannibal shales. 11, the 

 Chouteau limestone, with a few fossils. Number 12 is the 

 Burlington limestone with the characteristic basal fauna of 

 the Burlington. 13 is also the lower Burlington, carrying con- 

 siderable chert and containing the most prolific fauna in the 

 section. 14, 15 and 16 belong to the Burlington limestone ; the 

 upper portion containing the typical fauna distinctive of the 

 upper division. 



From Quincy southward the strata rise very gradually, 

 until the Burlington limestone, which appears a few yards 

 above the 'water level at that place, has an elevation of more 

 than 250 feet above the river, at Louisiana. Below the lime- 

 stone as will be seen from reference to the section, the beds 

 are principally soft shales, which are eroded much faster than 

 the great thickness of heavy, compact lime-rock overlying. 

 High hills with precipitous slopes are formed. These are 

 capped by the more indurated layers, rising in almost vertical 

 walls from about midway up the elevations. In consequence 

 of this, a peculiar and very striking phase of topography is 

 produced, reminding one very forcibly of the topographical 

 effects in a great driftless area of northeastern Iowa and the 

 adjoining States. 



North of Quincy, as already stated, the Burlington rock 

 dips below the water level of the Mississippi and does not 

 appear again until just above Ft. Madison, in Iowa, while at 

 the city of Burlington the base of the limestone is nearly 100 

 feet above low water-mark. At this place the organic remains 

 have received more attention than anywhere else, while the 

 vertical ranges of the different species have been determined 

 with great accuracy. From this locality, also, the extensive 

 faunas of the Kinderhook were first made known, and many 

 species described. 



A third of a century has passed since the investigations of 

 Hall, White, and Winchell brought to light so many interest- 



