360 W. H. WEED — COAL FIELDS OF MONTANA. 



Cokedale Section,. 

 Number Thickness 

 of bed. in feet. 



38 3,000 Green and gray shales, with interbedded sandstone, 

 poorly assorted. 



37 2,300 Sandstones of varying degrees of coarseness, poorly 

 bedded, of volcanic material, the finer-grained lay- 

 ers like volcanic tuffs, carrying leaf remains. 



36 2,500 Sandstones and local beds of conglomerate ; particles 

 subangular, wholly of volcanic material. 

 ^ 35 30 Conglomerate. 



34 140 Sandstone. 



33 2 Limestone. 



32 210 Sandstone. 



31 5 Coal. 



30 15 Shale. 



29 5 Coal. 



28 250 Sandstone; contains several seams of coal. 



27 75 Massive sandstone ; white, cross-bedded. 



26 150 Sandstone; " Tombstone " beds. 



23-25 1,150 Sandy shales and earthy limestones. 



^ J 22 25 Sandstone, fn-ming prominent hog-back. 



21 300 Calcareous shales, muddy limestones and sandy shales. 



20 30 Sandstone, with conglomerate belt at top. 



17-19 630 Dark gray earthy shales, with sandy belt in center. 



11-16 765 Earthy gray and blue shales, with two sandy belts. 



53 r 10 60 Quartzite. 



2 J 7-9 250 Red, earthy maguesian limestones and fissile sand- 



« '^\ stones. 



^ l^ 6 35 Conglomerate. 



,o f 3- 5 150 Red earthy sandstones and shales. 



2 30 Limestones passing into sandstones and grits ; Jurassic 

 fossils. 



■i 



St 1 200 "Mmcites beds." Limestones and shales. 



The section is represented graphically and in greater detail in the diagram 

 forming figure 2 in plate 13. 



The uppermost beds of the section form the valley of Billman creek. The 

 sandstones form bold combs and ledges, with intervening beds of very soft 

 and crumbly green clays. A detailed section of these beds, or of the beds 

 beneath, lying between them and the coals, is of comparatively little value, 

 as the sandstones vary both vertically and laterally from fine-grained rocks, 

 showing little evidence of bedding, to cross-bedded and rather friable sand- 

 stones, with local beds of conglomerate. 



Beneath these beds lie sandstones (number 36), free from clays but of 

 extreme variability, sometimes conglomeratic and often so fine-grained, 



