t 





19 1 7l FORSAITH—ALLOCTHONOUS PEAT 19s 



has been deposited in open water, while the very upper stratum 

 of swamps is as equally typical of a cumulative origin in place. A 

 microscopical examination of preparations from open lake deposits 

 shows much minute material, both organic and inorganic. The 

 inorganic constituent may be quite variable, depending upon the 

 character of the surrounding country. If the shores and bottom of 

 the pond are of a sandy nature, and the environment much broken 

 by hills or mountains, a condition favorable for rapidly flowing 

 streams, much sand may be found. On the other hand, if the land 

 is quite level and densely forested, the buoyancy of inflowing streams 

 is much reduced, and the inwash from the shores does not carry any 

 large amount of inorganic material on account of a turflike pro- 

 tection. Consequently, the peat found in such regions will be 

 more or less free from earthy inclusions. This difference in the 

 mineral content of peat in rugged and level tracts is significant, and 

 may throw light upon the topography of coal beds during the period 

 of deposition. All available evidence indicates that the external 

 characters of coal beds were very similar to those just mentioned, 

 inasmuch as the land was flat and heavily forested. 



Other inclusions found in peat are the calcareous remains of 

 Char a, limy silts, diatomaceous tests, and the shells of mollusks. 

 In addition to these mineral substances, which are small in amount, 

 there occurs the more strictly organic material, derived from more 

 or less macerated portions of plants and minute organisms of sedi- 

 mentary origin. Some of the most conspicuous of these elements, 

 as well as the most important from the scientific standpoint, are 

 pollen grains of the Abietineae and catkin-bearing angiosperms, 

 and spores from ferns, fungi, etc., representing bodies quite analo- 

 gous to the microspores and megaspores so habitually found in coal. 

 It is especially important to note that normally autocthonous 

 peats do not show the characteristic spore content so universally 

 found in open water formations. In addition to this microspore 

 material, one finds upon an examination of lacustrine samples a 

 rather large volume of amorphous material. Imbedded in the 

 flocculent matter, there appear ingredients the form of which is 

 more intact, such as woody and herbaceous plant fragments, 

 idioblasts from water lily stems, strips of cutinized epidermis, etc. 



