﻿CURRENT LITERATURE 



open water. The first hypothesis is almost universally accepted by geologists 

 and has received its main support from German investigations. The transport 

 theory of the origin of coal has always been strongly held in France. The 

 author is clearly in favor of the peat hypothesis {in situ or autocthonous 

 theory) and supports his views not only by a summary of the literature, com- 

 mendable on account of his generous fairness, but also as a result of his own 



We may next consider a work on the recent formations of vegetable 



recent decease of its author actually a monuments Potonie divides recent 

 deposits into the so-called Sapropelites, the Humus-Bildungen, and the Lipto- 

 bioliths. The first are deposits formed under open water by wind and water 

 transport, and correspond to the lacustrine deposits of the allocthonous 

 hypothesis of the origin of coal. The author is far from denying the actual 

 existence of large amounts of vegetable material laid down in open water, and 

 frankly admits that in the tropics, where the ravages of fungi in the case of plant 

 matter not permanently submerged are extremely rapid, such accumulation 

 is the only method of importance. In the case of temperate regions, however, 

 as represented by northern Europe, the true peat (Humus-Bildungen) predomi- 



considerable study of the plant population of peat moors, and his results will 

 doubtless be of great interest to students of plant geography and ecology. 

 Liptobioliths are the persistent, resinous, waxy, or cutinous remains of plants 

 which survive under the most unfavorable conditions as a result of their resist- 



result of his studies of recent accumulations of vegetable matter, that coal has 

 been formed for the most part from autocthonous peat (Humus-Bildungen), and 

 thus puts himself in line with the hypothesis most generally acceptable to 

 geologists at the present time. 



interest and significance is a recent bulletin of the United States Bureau of 

 Mines." This work represents the cooperation, as rare as it is desirable, of a 

 geologist, a botanist specially qualified in connection with the study of peat, 

 and a histologist trained in the laboratories of the University of Chicago, who 

 has given special attention to the actual organization of coal. The plates 

 accompanying the article are numerous and represent a degree of progress in 

 the difficult technique of the study of coal hitherto not found in any govern- 

 mental publication. On account of the different points of view of the authors 

 the results are not altogether harmonious. Perhaps the most interesting data, 



Berlin. 1908, i 9 n, and 1912. M. 8, 10, and 14 respectively. 



< White, David, Davis, C. A., and Thiessen, R., The origin of coal. Bull. 38, 

 U S. Bureau of Mines. 1915. 



