26 



PLATE 1 



Reflected plane polarized light, Ortholux Petrographic Microscope 

 Polished surface of Sample No. 1 



Figure 



1. Portion of core containing Sample no. 1. Contact between coal and lime- 

 stone is contorted and in part vertical. Slumping or squeezing in an ear- 

 ly stage of diagenesis is indicated. Coal is interbedded with limestone 

 lenses and shell fragments (light streaks in coal). Actual size. 



2. Vitrinite lenses (V), up to 60 \x thick and over 300 \x long, embedded in 

 a fine-grained groundmass. Exinite (E) is represented by small spores 

 and probably fragments of larger spores, not over 2 \x long. Pyrite (P) 

 is disseminated throughout the coal mainly as fine grains of a few mi- 

 crons in diameter and a few aggregates up to 15 [x in diameter. One large 

 quartz grain (Q) is in extinct position. Smaller quartz grains (extinct 

 position black, nonextinct gray) occur throughout the coal but cannot be 

 easily distinguished from coal or exinite. The fine-grained groundmass 

 is composed of argillaceous limestone and finely disseminated coal. 



25X oil immersion objective. Magnification: 250X. 



3. The vitrinite (V) of this specimen without interior preferred orientation of 

 the particles has an irregular and corroded appearance. No large spores 

 are present, as in the internally laminated bands (pi. 2, figs. 1 and 2). 

 Some small exinite fragments are among the black dots, but most of them 

 are calcite grains in extinct position. Pyrite (P) is somewhat less abun- 

 dant than in the other photographs. One quartz grain (Q), 30 to 40 \± in 

 diameter, is seen. 25X oil immersion objective . Magnification: 250X. 



4. The vitrinite (V) of this coal without internal orientation occurs predomi- 

 nantly as round, small grains, less than 10 [j. in diameter. They were 

 probably derived from larger pieces of vitrinite that disintegrated along 

 such planes of weakness as shown in plate 1, figure 5. 105X oil immer- 

 sion objective. Magnification: 1000X. 



5. Part of a vitrinite lens with irregular cell (?) structure. The vitrinite grains 

 tend to disintegrate along such planes of weakness into small vitrinite 

 bodies less than 10 ^ across (pi. 1, fig. 4). 105X oil immersion objective. 

 Magnification: 1000X. 



6. Fine-grained pyrite is disseminated in vitrinite along what probably were 

 former vascular strands. Besides much fine-grained pyrite in the ground- 

 mass, one large pyrite grain is shown around which the laminae are bent. 

 6 OX oil immersion objective. Magnification: 6 00X. 



