I9I1.] STEVENSON— FORMATION OF COAL BEDS. 85 



Lcpidodcndrou stems. The upper part is a pure typical anthracite. 

 Fish rQn\^ms.,Gyranthus,Mcgalichthys,e\.c.,occ\.\r throughout. The 

 plant remains are Halonia, in the form of crushed cyhnders of 

 wood. This condition and the mingUng of fish remains led Bolton 

 to conceive that the deposit was due to the bursting of a lagoon-like 

 swamp and to the discharge of vegetable debris, consisting of bottom 

 accumulations as well as of the twigs, etc., on the surface. He 

 refers, for illustration, to the bursting of Solway moss in 1771, 

 which spread over a square mile of ground, giving a mass of vege- 

 table matter, 30 to 40 feet deep, demolishing houses, overturning 

 trees and so contaminating the Esk that no salmon ventured into 

 the river during that year. 



Kuntze** took up the discussion from a botanist's standpoint and 

 advanced a wholly new theory. He antagonized v. Giimbel's con- 

 clusions which he maintains are wholly at variance with that 

 observer's facts. His own studies from 1879 to 1883 had shown 

 that the Carboniferous flora was sylvo-marine, a floating vegetation. 

 The objection that marine forms are wanting does not hold good: 

 the forms, described by v. Giimbel as resembling algae, are chitinous 

 bryozoans related to Aidopora. These, as stated by v. Giimbel, 

 occur abundantly in cannel and make up a great part of the boghead 

 coals. Carboniferous coals contain much sodium chloride, one 

 fourth to one half kilogram per ton; Tertiary coals contain none. 

 It is certain that the Carboniferous coals are not allochthonous ; the 

 flora must have been marine. 



He contends that students have failed to interpret Stigmaria 

 rightly, for the appendices, regarded as rootlets, are water leaves. 

 The Stigmaria, with intertwining rhizomas and hollow stems rising 

 above the water, formed floating islands. When overloaded, they 

 sank to the bottom and through the mud until checked by some 

 harder rock. He agrees with Potonie's conclusion that they ars not 

 allochthonous but he cannot concede that the underclay or clay shale 

 is a petrified humus, for the clay is no more a soil than are the 

 granite and other silicious rocks with which coal beds are often in 



" O. Kuntze, " Geogenetische Beitrage,"' Leipzig. 1895, PP- 4-2-77- Sincl 

 Carbonkohlen autochthon, allochthon oder pclagochthon ? 



85 



