Lesley.] 230 l^'^P"'' 



grain and fracture. As all the rocks of the Devonian system under 

 the western coal measures are very argillaceous, it is not well to re- 

 duce to powder the borings which come from the more sandy layers, 

 because then the prime distinction between sandstones and shales 

 vanishes. And yet it is well to keep one record tube of powdered 

 rocks, because the colored bands come out more plainly thus. 



To make a glass-tube record perfectly useful for the study of strata, 

 it is needful to cleanse such boi'ings as come up disguised in color and 

 consistency by oil. After oil is struck (however slight may be its 

 show) all the borings from further down, for many feet and even 

 fathoms, are stained and clotted with the oil, and should be cleansed 

 before being charged into the tube. 



Returning to the Brady's Bend Well, the glass-tube record shows 

 belts of orange from 142 to 202 ; from 371 to 390 ; from 525 to 550 ; 

 from 740 to 755; at 797; and from 890 to 908; all the intervals 

 being filled with olive and gray shales : 



Supposing the conglomerate at the river bank to be not over 50 

 feet thick, then the following are the probable identifications of these 

 orano-e bands : 



From 142 to 202 = 60 feet of red rock representing Formation XI. 



From 371 to 390 = 19 <' " " ^ . ^ . 



^ ^^r- rrr. ^r , ,, represcnting l^ormation 



From 525 to 550 = 25 '' " " I „i i . t, i -o j 



From 740 to 755 = 15 " '' " \ ^\', '""t ')' ^'^ fl^^ 



From 797 to 800 = 3 '' " " '' Mansfield ore, of lor- 



_, „„„ „„„ -.o . . ., mation Vill. 



From 890 to 908 = 18 " " " J 



It is impossible to identify these bands more carefully, because we 

 cannot be sure that they represent what are called red shale strata. 

 They may represent comparatively high-colored rocks charged with 

 nodular iron ore, and giving flows of iron rust water. This much is 

 certain; there is no resemblance whatever between this scheme of 

 orange bands in the B. B. Well, and the so-called red rocks in the 

 Sligo Well section, 



Plate IV will show the distance and direction from one another 

 of these two wells, and their geographical relations to the Oil Creek 

 region and to Pittsburg. 



At the bottom of the map close to the Pennsylvania and Virginia 

 State line will be seen the wells of Dunkard's Creek, sunk through 

 the lower part of the Upper Coal Measures, into the upper strata of 

 the Middle or Barren Measures, below the Pittsburg Coal ; as the 

 following record, by Mr. Robert Collyer,* of the Amber Oil Com- 

 pany's (now Amber Gold Mining Company) " Kener Well," on Deer 



