12 



MAZOCARPON OEDIPTERNUM 



served and apparentl}^ similar to those 

 in coal-balls. Kubart (1911) later re- 

 examined some of Corda's original ma- 

 terial but was unable to obtain any new 

 specimens or ascertain the original 

 source. Nemejc (1937, p. 687) has char- 

 acterized the floras of Carboniferous 

 strata of the region and concludes that 

 they range in age from the transition at 

 the top of Westphalian B into the Per- 

 mian but that the lower Stephanian is 

 not present. Presumably Corda's coal- 

 balls came from somewhere in this se- 

 quence, probably (judging from the fos- 

 sils) from the upper Westphalian. Little 

 is known about fossil plants in coal- 

 balls reported by LeClerq (1925) from 

 the Petit Buisson coal (Aegir) horizon 

 in Belgium. Fossil plants in coal-balls 

 from the Katharina coal in Limberg in 

 Holland and the Aachen district in Ger- 

 many are well known, chiefly through 

 recent investigations by Hirmer. Lists 

 of species present and other references 

 are included in his papers cited for 1928 

 and 1938. This bed is generally accept- 

 ed by European geologists as the bound- 

 ary between Westphalian A and West- 

 phalian B. Coal-balls are reported by 

 Zalessky (1910) from the Donetz basin 

 in Russia, the most important of which 

 seem to be slightly older than the Kath- 

 arina horizon and therefore in the West- 

 phalian A, but no very thorough studies 

 are known to have been made. 



The most important of all European 

 coal-ball horizons occurs in the lower 

 part of the Westphalian A. One per- 

 sistent coal bed, which may be traced 

 from Westphalia into Belgium and is 

 recognized in central England by the 

 presence of an overlying characteristic 

 ''marine band," has provided the ma- 

 jority of species of coal-ball plants now 

 known. Among them is Mazocarpon 

 shorense Benson. Important work was 

 done on coal-ball fossils from this bed 

 by English botanists particularly. In 

 England the coal seam is known as the 

 ''Halifax" or "Hard Bed" coal, as the 

 "Bullion", "Mountain mine" etc. In 

 Lancashire, where it splits into two 

 beds, the upper bed is often called the 

 "Upper Foot Seam" and the lower one 

 the "Canister". In Belgium the cor- 

 relative seam is the "Bouxharmont" 



and in Limberg (Holland) and in the 

 Ruhr it is the " Finef rau-Nebenbank ". 

 Because of its importance as a source 

 of coal-ball plant fossils this horizon 

 may be termed the Great Coal-ball hor- 

 izon. It seems that for many years coal- 

 ball fossils found in this country and 

 elsewhere will require comparison with 

 forms previously described from this 

 Great Coal-ball horizon, as it is the only 

 one whose flora is adequately known. 



Stopes and Watson (1909) showed 

 that the seam which contains coal-balls 

 long known from localities near Staly- 

 bridge and Hough Hill was lower than 

 the Ganister (Great Coal-ball) horizon. 

 Miss Benson also obtained Mazocarpon 

 shorense from these localities. Coal-balls 

 were also reported by Stopes and Wat- 

 son from above the level of the Great 

 Coal-ball horizon in central England in 

 the "Great Harwood" seam, and in 

 the ' ' Arley mine ' ' coal at the top of the 

 "Lower Coal Measures" (Upper part 

 of the Lanarkians). Floras from these 

 coal-balls have not been described to the 

 author's knowledge. 



Kubart (1908, 1914) described a few 

 very interesting pteridospermic species 

 from coal-balls in the Koksfloz in Lower 

 Silesia whose occurrence had been de- 

 scribed by Stur in 1885. The strati- 

 graphic position is apparently well de- 

 fined, as this seam is the highest in the 

 Rand group, with marine beds above it, 

 and the Pochhammerfloz, lowest coal of 

 the Sattelfloz group, is superjacent at a 

 short interval. The boundary between 

 the Rand and the Sattelfloz groups re- 

 cently has been more precisely corre- 

 lated with standard sections by Czar- 

 nocki. Bode, and others (cf. C. R. 2nd 

 Heerlen Congress). 



Coal-ball plants were reported by Ab- 

 salom in 1929 from the Little Lime- 

 stone coal of the Lower Limestone group 

 in the Carboniferous Limestone series 

 of Northumberland. Thus far the oc- 

 currence is chiefly significant because a 

 few species seemed to be present which 

 had previously been identified from the 

 Upper Carboniferous Great Coal-ball 

 horizon. If they are correctly identified 

 (Crookall, 1939, does not accept the 

 determinations without reservation) 

 these species transgress the important 



