562 POPULAR SCIENCE MONTHLY 



stantly augmenting and at the same time undergoing decay. This is 

 finally expressed in the deep black color of the stratum, by the car- 

 bonized fragments of marine algae, driftwood and even of bones, show- 

 ing that within this zone there are developed precisely those conditions 

 which would be productive of gases in considerable volume. 



It is this last explanation which affords the chief basis of a tenta- 

 tive hypothesis respecting the origin of the gases producing the con- 

 flagrations, though it is also highly probable that other volumes of 

 gas originated at a greater depth in a buried marsh, or in silt deposits 

 which were subsequently overlaid by a pebbly beach. 



This phenomenon, while peculiarly interesting in itself, serves as 

 a means of explaining the possible origin of many obscure forest fires 

 for which it has hitherto been impossible to find an adequate explana- 

 tion, and in considering this important aspect of the question we are 

 not to overlook the possibility of accounting for fires which have oc- 

 curred in past geological ages, as well as those of recent date. 



In 1905, Arthur Hollick directed attention to the presence of 

 charred wood in the Cretaceous deposits at Kreischerville, Staten 

 Island, New York, and drew the inference that since man was not 

 in existence at that time, the fire must have been due to some natural 

 agency, probably lightning. This explanation, however, was not re- 

 garded by him as wholly satisfactorj', and it was adopted tentatively 

 because of the absence of positive testimony in any other direction, 

 and also because the occurrence of fires in widely separated localities 

 of approximately the same geological age could not be accounted for 

 through the medium of such an agency. 2 In a more recent communi- 

 cation on this subject, 3 the same author observes that some of the 

 fragments of burned wood are charred on the outside only, while other 

 smaller fragments are completely charred throughout. " These latter 

 occur in greatest abundance in connection with layers or seams of 

 yellowish, sandy clay. The prevailing colors of the Cretaceous sands 

 and clays throughout this locality are white and gray, while the yellow 

 layers are of quite limited extent and appear to have been burned 

 or baked. It seems therefore reasonable to infer from this association 

 of materials, that the charred wood was not deposited with the clay 

 in the condition of charred wood, but that it was fresh material at 

 the time of deposition and was subsequently burned in place, thus 

 baking the enclosing clay." 



"A careful study of the Kreischerville deposits indicates very 

 clearly that the original conditions of deposition must have been 

 strikingly similar to those described as existing at the Kittery Point 

 Beach. The layers of vegetable debris and sand, intercalated in 

 the clays are comparable to the sandy layer of black, organic debris 



2 Proc. Nat. Sci. Assn. 8. I., Vol. IX., 1905, pp. 35, 36. 

 8 Proc. 8. T. Assn. Arts and Sciences, Vol. I., 1906, p. 21. 



