522 A. G. LEONARD 



of the joint cracks. In places, these beds are composed of thin 

 layers of black shale and gray, very sandy shale, or sand. 



On the Heart River, south of Almont, the following section 

 appears, embracing portions of both the Lance and Fort Union 

 formations : 



Feet 



5. Sandstone, yellow, soft, massive 50 



4. Shale, yellow and light gray 61 



3. Sandstone, white 30 



2. Sandstone, yellow and brown below, gray toward top. The upper 



sandstone of the Lance formation 95 



1. Shales, dark colored 180 



416 



Nos. 1 and 2 belong to the Lance formation, while the three 

 upper numbers are Fort Union. On the Heart River in the vicinity 

 of Mandan and in the bluffs of the Missouri near Bismarck, the 

 Lance beds are made up chiefly of the dark shales, as is evident 

 from the two sections which follow. The first is exposed at the 

 east end of the Northern Pacific railroad bridge over the Missouri 

 River. 



Feet Inches 



Drift, resting on the eroded surface of the Lance formation 15-20 



Shale, dark gray to black, with thin, light gray streaks; cut by 

 many joint cracks several inches apart. Faces of the joints 



stained by iron 42 



Shale, sandy, black 1 



Shale, black 3 6 



Sandstone, dark gray to black 1 



Shale, black 2 6 



Sandstone, yellow 4 



Shale, dark gray to black, alternating with yellow, fine-grained 



sandstone and sandy shale 22 



Shale, black 30 



Unexposed to river level 15 



Total 141 



The second section appears on the south side of the Heart 

 River two miles above Mandan, and is as follows: 



