1887.] 1^5 [Stevenson. 



is exposed at the end of this interval. Tlie exposure shows only five feet, 

 but the fragments indicate a thickness of fully thirty feet. The rock 

 is light gray, some parts are very hard and in thick layers, but others are 

 in thin layers ; the dip is nearly fifty degrees. 



This rock is succeeded by shales ill-exposed and extending nearly 400 

 feet to the eighth mile post. The exposure is so poor that the dip could 

 not be ascertained, but it may be taken as averaging not far from thirty- 

 five degrees. Here belong the coal beds, to which reference has been 

 made, and one of them is mined on the opposite side of the river. 



From the eighth mile post for 1175 feet, everything is practically con- 

 cealed. Clearly enough the interval is occupied by gray to bluish sand- 

 stones and shales, but there is no exhibition good enough to tell the rate of 

 dip. An uncertain measurement almost midway in the interval made the 

 rate not far from twenty-five degrees. As the next exposure shows a dip 

 of only fifteen degrees, the dip in this concealed interval may be averaged 

 at twenty degrees. 



This is succeeded by a reddish or bluish sandstone, fortj^ feet thick, 

 which is well shown in a cliff on the hillside but does not appear in any 

 of the railroad cuts. The dip is fifteen degrees. 



No further exposure occurs for 200 feet, bej^ond which comes a sand- 

 stone with dip of ten degrees. This is shown as a cliff, but it was not 

 seen in the cuts ; it continues for a horizontal distance of 600 feet. The 

 color varies from gray to rusty brown and the rock is fine-grained but 

 irregular in bedding. 



This is succeeded bj^ a concealed interval of 375 feet, in which the dip is 

 twelve degrees ; beyond it one comes to red sandy shale extending 300 

 feet with dip of twelve degrees. Upon this rests a red to gray, irregu- 

 larly bedded sandstone continuing for 200 feet, also with dip of twelve 

 degrees. After a concealed space of ninety feet, sandstone, gray to red, 

 is reached, which, with dip of fourteen degrees, extends for 300 feet along 

 the track. It contains many thin beds of red shale and some insignificant 

 beds, or rather streaks, of impure limestone or possibly only calcareous 

 sandstone. Above this are alternations ot red sandstone and red shale, 

 with dip of fifteen degrees and continuing for 2300 feet to Back creek just 

 beyond Tyler's coal switch. Next comes the geodal limestone, to which 

 reference has been made so frequently and which belongs at the base of 

 the Knox limestone. Evidently the fault of Walker mountain has been 

 crossed ; so the succession may be summarized. It is as follows : 



Lower Silurian. 



Limestone in bank of Back creek 25' 



The Walker Mountain, fault. 

 Lower Carboniferous. 



1. Red sandstones and shales 570' 



2. Sandstone, red to gray with some shale 73' 



3. Concealed 23' 



PROC. AMKR. PHILOa. 80C. XXIV. 125. N. PRINTED MAY 3, 1887. 



