100 PROCEEDINGS OF THE INDIANA ACADEMY OF SCIENCE. 



in no instance, as yet, have any workable beds of coal been found associated 

 with these limestones." He states that in the southern portion of its range 

 through Indiana the subcarboniferous has numerous alternations of sand- 

 stones in its upper part (constituting the Huron formation of present nomen- 

 clature) and to that group of the subcarboniferous which we now call the 

 Mitchell limestone he gave the name "Barren Limestones," because they 

 prevail through the Barrens of Harrison, Orange and Lawrence Counties, 

 which he states were covered with a stunted growth of black jack oak. He 

 mentions the characteristic sink holes and disintegrated cherts which accom- 

 pany this formation, and states that, though called barren, its surface is 

 capable of producing excellent crops. This barren limestone "passes down- 

 ward into fine-grained freestones with subordinate beds of gray shales to 

 which the name of Knohstone may be appropriately applied, since these sili- 

 cious strata weather into peculiar knobs or hills." In this sentence Dr. Owen 

 therefore gave the name which it still holds to a prominent formation of south- 

 ern-central Indiana and which, in his second report (1838) he correlates with 

 the Waverly of Ohio. He states that it extends from Floyd and Harrison 

 Counties northward through .Jackson and parts of Monroe, Morgan and 

 Hendricks Counties, thus mentioning most of its present known distribution. 



"At the base of this knobstone, " he continues, there "occurs an important 

 stratum — the black hiiuminous aluminous dale — which is to be seen, when 

 the water is low, at the New Albany Ferry-Boat landing. I call it an important 

 stratum, because this black bituminous slate resembles, both in its external 

 appearance and chemical composition, the (-oal shale; and since it takes fire 

 and burns for some time, owing to the presence of bitumen and sulphuret of 

 iron, it is frequently mistaken for indications of coal, and even for coal itself. 

 In no instance have I ever found it associated with perfect seams of coal; 

 and I have but little hesitation in asserting, that no true coal will ever be 

 found associated with it in our section of the country." He emphasizes this 

 latter statement by placing it in Italics in his summary at the end of his report, 

 and the writer, while serving as State Geologist, had also to emphasize it, 

 as on several occasions persons claimed that they had discovered coal in 

 Johnson County, ami <-oinpanies were even organized to sink shafts for its 

 develojMiient. 



"Under the black slate," continues Dr. Owen, "and interposed between 

 beds of crinoidal and coralline limestones is a valuable bed of hydraulic 

 limestone varying in thickness from two to ten feet." This is our Silver 

 Creek limestone afterward used so extensively in Clark County for the 

 making of natural rock cement. He referred the black slate and accompany- 

 ing underlying limestones to the Devonian system of rocks, the crinoidal layer 

 being what is now known as the Sellersburg limestone while the coralline 

 limestone we call the Jeffersonville. He next recorded the presence of the 

 "Magnesian limestones" of the Upper Silurian group, and finally, as consti- 

 tuting the surface rocks of Switzerland, DearlxH-n and other counties of 



