o 



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



Slide. The following section shows the sequence of the beds from the coal- 

 beariug strata down to the Carboniferous limestones (the same sequence being 

 represented graphically in plate 13, figure 1) : 



The Cinnabar Section. 

 Numbe?' Thickness 

 of bed. 171 feet. 



•| I 29 800 Sandstones, containing coal. 



g ^ 28 5 Coal seam. 



^^ 1 27 125 Sandstones, white, massive, cross-bedded. 



^ I 



f 26 240 Fissile, argillaceous sandstones and shales. 



25 450 Shales, generally crumbly, with layers of black bituminous 

 shale and harder sandy ledges. 



24 225 Shaly sandstones and limestones. 



23 40 Sandstone. 



22 165 Sandy, splintering, gray shales and limestones. 



21 500 Black bituminous shales. 



20 40 Limestone. 



- 19 400 Black shales, sometimes arenaceous. 



18 10 Sandstone. 



17 250 Black and dark-blue shales. 



16 15 Sandstone. 



15 75 Sandy shales. 



14 10 Sandstone. 



13 340 Thinly laminated arenaceous shales. 



12 15 Sandstones. 



11 75 Shales. 



flO 30 Quartzite. 



j 9 10 Limestone. 



g I 8 150 Sandy shales. 



-^ ^ 7 50 Red earthy limestones, magnesian. 



6 40 Conglomerate. 



5 95 Sandstone and shales. 



4 151 Sandstone. 



85 Red earths. 



20 Coarse, arenaceous limestones. 

 160 " Myacites beds." Earthy, crumbling limestones. 



The lowest beds in this section, designated as Jurassic, are earthy, crumbling 

 limestones, characterized by numerous fossils, Myacites subcompressa being 

 extremely abundant, together with many other forms common to the Rocky 

 Mountain Jura, such as Gryphcea, Pinna, Ttngonia, Gervilliay Pentacrinus 

 asteriscus, etc. 



