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



peat. The brown flocks are sources of dopplerite. There is no 

 sharp separation between dopplerite and the surrounding peat — 

 there is always a passage zone, an intermingling of peat and dop- 

 plerite. 



The mode of occurrence is variable. In many places, he saw 

 veinlets, one to two meters long and one to five centimeters wide ; 

 here and there a vein spreads out from a root — one passed over a 

 thin sandstone and was prolonged horizontally for several meters as 

 a little bed, at most two centimeters thick. At the same place, he 

 observed some wedge-shaped veinlets penetrating the glacial drift 

 to a depth of 3 to 4 centimeters, where it filled cracks in the clay, 

 binding the fragments into a breccia. There were no plant remains 

 in the clay, so that the fine gelatinous dopplerite must have been 

 deposited in already existing cavities. The presence of abundant 

 water being essential to the ulminification, the mineral is found espe- 

 cially in the lower part of the peat. As every plant can become 

 ulminified, dopplerite may occur in any moor, where the temperature 

 and moisture are in proper relation. He has found the mineral 

 derived from Sphagnum at the contact between Rasenmoor and 

 Hochmoor, where the water-rich condition existed. 



Kaufmann believed that with the point of a knife he separated 

 particles of dopplerite from good peat ; Friih did this with Marmor- 

 torf, but he thinks that even the best Rasenmoortorfs are not usually 

 so far advanced as that. The microscope detects little flakes pro- 

 duced bv the flowing together of very tender ulniin material, if the 

 peat be ripe ; but one cannot determine whether these are ulmic or 

 humic acid — the quantity is too small. At the same time, he main- 

 tains that it is an error to identify with dopplerite the caustic potash 

 extract from peat, as Kaufmann and Muhlberg have done, for potash 

 combines with ulmic and Immic acid alike. Dopplerite is a higher 

 member of the ulmin grou]). 



Kinahan'"' often observed that, when peat was taken out on the 

 hills near Dingle bay, little streams of tar, which had filled tubes 

 made by decav of roots, oozed and trickled out from the newly made 



"" G. H. Kinahan, Geol. Surv. of Ireland, Explan. of sheets 182, 183, i<)o, 

 1861, p. ii. 



1S2 



