622 STEVENSON— FORMATION OF COAL BEDS. [November 3. 



The plants and the conditions arc those of a peat moor. The 

 mosses belong to the peat-forming group; the reeds and sedges are 

 swamp plants to which also belongs the bogbean (Mcnyaiithes) of 

 which the seeds are abundant in both the coal and the partings. 

 Spruce is present only in the lowest bench but birch and fir (Pimts 

 sylvcstris) are in the higher benches. The trees are those of the 

 swamps. The animal remains belong in part to a swamp fauna, 

 there being great abundance of insect wing-cases on surfaces of the 

 peat and clay layers, while with them are shells of freshwater mol- 

 lusks. The larger animals are mammals. Everything goes to show 

 that this Schieferkohle is a compressed, dried out peat and the older 

 opinion — that it originated from drifted wood — is incorrect. 



In his later work, Heer gives additional facts respecting Diirnten 

 and some noteworthy observations concerning other localities. At 

 Diirnten, a wedge of sand and pebbles separates the main mass from 

 a 6-inch layer of peat and stems above. The main portion is hori- 

 zontal, while the thin layer dips toward the place of union and the 

 sands overlying it have the same dip. At Unterwetzikon the lignite, 

 underlying 12 to 30 feet of stratified sands and gravel, rests on a 

 marl with freshwater shells. At Utznach, there are two beds, 5 

 and 3 feet, separated by 16 to 20 feet of light colored marly mate- 

 rial, and the lignite retains its original horizontal position. At 

 Morschwyl, the lignite is 2 feet thick, with vertical tree stems, the 

 whole marly deposit, including the lignite, being 8 feet thick and 

 underlying 26 feet of detritus. At another locality, the cover is 

 70 feet and the deposit is 3 feet, with vertical stems, 6 feet high 

 and 3 feet diameter, extending into the marl above. This lignite 

 underlies and overlies marl, the whole mass being about 16 feet thick. 

 Heer gives a list of the plants recognized at the several localities and 

 discusses their relations, showing that the grouping is clearly that 

 observed in peat bogs of northern Europe. 



V. GiimbeP^^ studied this Schieferkohle from many places in 

 Switzerland and southern Bavaria, his typical locality being Mor- 

 schwyl. In l)oth the partly loose peat-like and the partly dense 

 pitchcoal-like i)ortions, numerous horizontal-lying fragments of 



"' C. W. V. Giimliel, " Beitrjige zur Kenntniss," etc.. pp. 135-138. 



220 



