JEFFERSON COUNTY. 



723 



THE LOWER BARKEN MEASURES. 



The Lower Barren Measures of western Pennsylvania have a typical 

 representation in Jefiferson county. The series is about 450 feet in thick- 

 ness, and consists here chiefly of olive and red shales, with intercalated 

 bands of red and yellow sandstone, two or more strata of limestone a,nd 

 two or three small seams of coal. About the middle of the Barren Meas- 

 ures occurs a limestone which is remarkably persistent in place and 

 uniform in character. It varies somewhat in thickness, but is usually 

 from three to five feet, is gray in color, and contains numerous and char- 

 acteristic fossils; these are largely portions of crinoids, and hence we 

 have called it the Crinoidal limestone. Perhaps the most abundant fossils 

 contained in it are the spinous plates of Zeacrinus macrospondylus. It also 

 contains many moUusks, such as Spirifer cameratus, S. Keinluckensis, Retzia 

 punciulifera, Produdus longispinus, P. semireticulatus, P. Nebracensis, Hemipro- 

 nites erassVrS, and Chonetes Smithii, and numerous fish teeth of the genera 

 Cladodus, Petalodm, and Oteno'plychius. In the northern part of the county 

 the crinoidal limestone caps the hills bordering Yellow Creek, and the 

 red and green shales which underlie it are conspicuously shown on the 

 hillsides above Salineville and Irondale. 



Passing southward from the valley of Yellow Creek, the first oppor- 

 tunity of measuring the distance between the Pittsburgh coal and the 

 first of the lower group — the " Groff Vein," Coal No. 7 — occurs near Knoi- 

 ville. Here the distance between the Pittsburgh Coal and the crinoidal 

 limestone, as measured by barometer, is about 165 feet. In the section 

 taken from Richmond to Brown's Station, the interval between the Pitts- 

 burgh seam and the crinoidal limestone is 207 feet, and the distance 

 from the Pittsburgh seam to Coal No. 7 at Fleming's mine is 423 feet. 

 In the section from the highlands down to the mouth of Wills' Creek, 

 the distance from the Pittsburgh seam to the coal beneath the crinoidal 

 limestone — the limestone itself not being seen — is 230 feet, and to Coal 

 No. 7 is 488 feet, to Coal No. 6 552 feet. At Steubenville Coal No. 7 is 

 apparently wanting, and the interval between the Pittsburgh coal and 

 Coal No. 6, the "Shaft coal," is at the rolling-mill shaft 506 feet. At 

 Boreland's shaft it is 198 feet from the Pittsburgh coal to the crinoidal 

 limestone, and 511 feet to the shaft coal.* At Mingo Station the dis- 



* I am told by Mr. John Lo\re that measurements carefully made by the county 

 surveyor shnw that at Averiek's shaft, which is 204 feet deep, the Pittsburgh coal lies 

 385 feet above the shaft mouth, making the distance between the two coals 569 feet. 

 The same authority reports the distance between the Pittsburgh and shaft coals at 

 Spaulding, Woodward <fc Go's shaft, to be 534 feet. The measurements given above and 

 on our charts were from observations taken with the aneroid barometer, by several 



