214 



THE AMERICAN MONTHLY 



[November, 



clastic materials (clayish slates and 

 sandstones). There are found three 

 constant types of these bodies: — 



a. Flat or subcylindrical bodies 



of filamentous and ramified 

 structure. 



b. Flat or subcylindrical bodies, 



forming simply filaments. 



c. Flat, rounded, and various 



shaped bodies of granulated 

 structure. 



Between these three types are 

 found forms containing filaments, 

 connected with granulated bodies, 

 others with bodies of fibrous and 

 granulated structure. The latter bo- 

 dies are commonly found v/ith regu- 

 lar limited circumference and equal 

 extension in the three dimensions, 

 other bodies with irregular limited 

 circumference and prepondarant lon- 

 gitudinal extension. The bodies of 

 some of these types exhibit, from 

 their constancy, the qualities of orga- 

 nic individuals. 



Dispersed through all coal beds of 

 the carbon, in free and isolated state, 

 specimens are found of these curious 

 bodies, the size of which does not 

 vary much for the single forms. The 

 largest form is found from 2 to 3 

 millimetres in length, the minutest 

 0.20 millimetre diameter. All these 

 bodies belonging to this group of con- 

 stituents of coal exhibit considerable 

 regularity in their histological ele- 

 ments. These elements, granules 

 and fibres, generally of the same size 

 and shape, appear constantly com- 

 posed of the same non-polarizing sub- 

 stance. Globular bodies of more 

 homogeneous nature, and generally 

 of the same diameter, are constantly 

 found as accessory constituents to 

 the body of the substance. 



These bodies are not unfrequently 

 found separated from the body from 

 which they arose; doubtless they must 

 have been in some genetical con- 

 nection, as the same bodies are ob- 

 served still connected with it, and 

 some of the globules evidently not in 

 a developed state. 



A great many of these bodies ex- 



hibit remarkable transmutations, ef- 

 fected in the structure, as results of 

 immediate contact with the yellowish 

 semi-transparent substance of the 

 nodules, enclosed in the principal 

 constituent of the coal. The regular 

 radial position of the molecules of 

 the spheres of this substance becomes 

 altered: some particles of the body,, 

 being in contact with, and partly his- 

 tological elements of, the latter be- 

 come separated from the whole body; 

 and particles mixed up with and en- 

 veloped in the polarizing yellowish 

 substance are found inside the, trans- 

 muted spheres. Bodies of filamen- 

 tous and fibrous structure in contact 

 with the spheres are turned off from 

 their regular position; the zone of 

 contact of the substance is dispersed 

 into filaments and fibres, still distin- 

 guishable from the polarizing sub- 

 stance; bodies of granular structure 

 are resolved into cellular granules of 

 the same size and shape, the latter 

 sometimes separated from the whole 

 body, and enveloped in the polarizing 

 substance. 



Within the layers of the various 

 substances of the carbon coal bed 

 are found layers of clastic mineral 

 substance from microscopic size up to 

 several centimetres in height. These 

 clastic microbeds constantly contain 

 fragments derived from the substan- 

 ces of those microbeds being in imme- 

 diate contact. In many cases com- 

 plete and connected groups are still 

 seen in immediate connection with 

 the substance from which they arose, 

 and enclosed within the clastic sub- 

 stance. In many cases the histolo- 

 gical structure and the general feature 

 of the substance, in this isolated 

 state, can be seen very much more 

 clearly than is possible in an accu- 

 mulated state in the pure microbed of 

 the substance. 



Some of these microbeds of clastic 

 substance contain very well-preserved 

 fragments of cellular and vascular 

 plants. Some varieties of spores of 

 vascular cryptogams of uniform size 

 and shape are found mixed up with 



