532 E. RUSSELL LLOYD AND C. J. HARES 



Ft. In. 



Lignite i 1 1 



Sandstone and shale, sandstone in upper part and shale 



below 27 o 



Lignite • ■ ■ 10 



Shale II o 



Lignite = 3 o 



Shale 3 4 



Sandstone, hard ledge in upper part 13 2 



Lignite 5 3 



Shale I 8 



Lignite i 2 



Shale I 4 



Lignite S ° 



Shale 8 6 



Lignite 6 11 



Shale '. 4 8 



Lignite 6 



Shale 7 6 



Lignite 5 4 



Sandstone iS 4 



Shale 



250 II 



Section Along North Fork of Grand River at Bloom, South Dakota^ 



Fort Union formation( ?) ^t- ^'^• 



1. Sandstone, brown and yellow, fine-grained, thin-bedded, 

 interbedded with lenses of compact, bluish-gray lime- 

 stone 



Cannonball marine member of the Lance formation 



2. Sandstone, dark gray, very calcareous, marine fossils 

 Nucula sp., Callista deweyi, Pholas sp., Corbula sp., 



Anchura americana 10 o 



Ludlow lignitic member of the Lance formation 



3. Lignite 2 o 



4. Shale and sandstone, interbedded 40 o 



5. Lignite i ° 



S3 o 



Note. — No. i was considered as Fort Union but very possibly is Cannonball, as 

 indicated by more recent field work in other parts of the field. 



' See footnote, p. 533. 



