436 STEVENSON— INTERRELATIONS OF FOSSIL FUELS. 



laria, a smaller number of Calamites and still fewer ferns ; but in 

 the field of Lower Silesia, though tree-like Lepidodendron and Sigil- 

 laria are not wanting, the prevailing forms are Stigmaria, Equisetuin 

 and ferns. Cannel-like coal occurs in the lowest seam. 



From the Silesian-Bohemian line to beyond Altwasser, the Car- 

 boniferous rests on Transition rocks, but beyond Altwasser, usually 

 on gneiss and mica schist of the Eulengebirge. In this, the Walden- 

 burg district, the Hangend is red sandstone with occasional layers 

 of limestone, containing fish remains but no plants ; coal appears to 

 be wanting but a black bituminous shale, 24 to 30 feet thick, is 

 plant-bearing. 



The lower coal group (Waldenburg) has many coal seams with 

 a maximum thickness of about 43 feet, but the variations are great. 

 A seam near Albendorf, 22 inches, splits into layers an inch to a 

 half inch thick, of which the surfaces are covered with Stigmaria 

 ficoides. Mineral charcoal is not abundant in this coal ; the sand- 

 stone contain much petrified wood. Another seam, near Forste, 

 yields a hard bituminous coal but the numerous clay parting make 

 the seam almost unworkable ; the coal contains Stigmaria, Sigillaria, 

 Sagenaria and Calamites. The roof shale usually has a varied as- 

 semblage of plants, but at one locality Calamites is predominant. 

 Goeppert saw, in the sandy roof of the highest seam, 4 vertical stems 

 of Sagenaria, without roots, standing on the coal. In their interiors 

 he found remains of Calamites. 



Near Altwasser this group has 37 coal seams, but near Wald- 

 chen there are only 2. Near Ober-Altwasser, 15 seams were seen, 

 of which 6 can be worked, being 20 to 30 inches thick ; but the dip 

 is high, 60 to 70 degrees. Ordinarily, the coal in this neighborhood 

 is laminated and, when split, the surfaces show Stigmaria ficoides 

 as well as Sigillaria, Sagenaria and Calamites. The roof of seams 

 2 and 10 is, in each case, a mass of Alethopteris fronds, closely 

 packed and associated with a very little clay. This condition was 

 found persistent for 4,800 feet in one mine on seam 2. Stigmaria 

 abounds throughout this lower group, not only in the clays, but also 

 in the coal itself. Goeppert emphasizes many times the difference 

 in species observed in superimposed coal seams as well as in the 



