12. PENN TOWNSHIP. F 2 . 293 



Volatile matter, 8. 83 



Fixed carbon, 78. 83 



Sulphur, 67 



Asb* 9. 39 



Nothing further need be said concerning this coal. The 

 facts speak for themselves. Nor is there any probability 

 that results appreciably different would be yielded by the 

 other two seams which accompany this and may, like it, be 

 traced along the mountain by the slight terraces at their 

 outcrops. 



The Maucli Chunk red shale, JYo. XI. 



This red shale occupies the whole trough or basin of the 

 cove. Its beds dip regularly from the mountain on both 

 sides, and become nearly horizontal along the middle line 

 of the syncline. Its decay affords good farming land, and 

 the cove, sheltered as it is from winds by the mountain 

 ranges which almost surround it, is one of the best farming 

 districts in the county. 



Some of the beds of the Mauch Chunk red shale are cal- 

 careous enough to render the water hard. 



Iron ore. 



A thin bed of poor nodular iron ore accompanies one of 

 the coaly layers in the Pocono sandstone. Specimens of 

 the nodules have been analysed, and the percentage of phos- 

 phorus is so high as to suggest a coprolitic origin. 



The great weight and yellow rusty color of the fragments 

 of rock (dolerite) along the lines of the trap-dykes (described 

 below) have deceived people into believing that they were 

 masses of iron ore, and attempts have even been made to 

 open mines upon the trap. But, of course, the material 

 was rejected by iron-makers. Trap is not iron ore, although 

 grains of magnetic iron are scattered through it. 



The trap-dykes of the Cove. 



Trap-dykes are ancient cracks in the earth filled from be- 

 low by lava which has hardened into rock. They must be 



