116 STEVENSON— FORMATION OF COAL BEDS. [April 21. 



100 years and the relations of the beds had been described by several 

 geologists ; but nothing was known which showed the mode in which 

 the coals had accumulated. The section contains about 100 coal 

 beds, of which fully 25 attain workable thickness in much of the 

 area. Gothan had already discovered underclays with roots asso- 

 ciated with Mesozoic coal beds on the Yorkshire coast of England, 

 and it seemed probable that search for similar clays at Fiinfkirchen 

 would be successful. 



He was not disappointed, though he found the difificulties in the 

 way of study greater than anticipated. 



Under the coal bed, no. 7, there is a well-marked undcrclay with 

 irregular branching coaly markings, varying in diameter and in every 

 respect resembling roots ; and, at one locality, a rhizoma with its 

 rootlets was complete, enabling him to determine the relations of 

 the other forms. " Through such horizontal rhizomas, the analogy 

 of this Mesozoic underclay with the Carboniferous Stiginaria-heds 

 and the recent or sub-recent reed-beds is the more marked." A 

 four-inch layer of carbonaceous shale lies between the underclay and 

 the coal, but one cannot trace the roots in it ; they cannot be dis- 

 tinguished in the dark material, which is so crossed by cleavage 

 planes that none but irregular angular fragments can be obtained. 

 The planes do not coincide with the direction of the rootlets. 



Roots are seldom observed in the freshly exposed rock within 

 the mines, but they are distinct enough where the rock is somewhat 

 weathered. Gothan exposed the outcrop for several meters at dif- 

 ferent horizons and in the course of a day's excursion, he found 

 well-marked underclays, with roots, associated with 8 coal beds. 

 The analogy with Tertiary and Quaternary underclays is complete. 

 His conclusions arc that the underclay, associated in more than a 

 dozen instances, with the Fiinfkirchen coal beds, shows that these 

 are, for the most part, of autochthonous origin, as are, predomi- 

 nantly, the younger and older humus deposits of the present time 

 as well as those of the Tertiary and Palaezoic. The failure to secure 

 ])roof of this origin for all the Funfkirchcn beds is due merely to 

 the unfavorable conditions to which reference has been made. In 

 a footnote he notes his discovery of typical underclay, with roots, 

 just below a Wcalden coal bed in a neigliboring district. 



116 



