134 B. SHIMEK AFTONIAN FOSSILIFEROUS GRAVEL AND SAXD BEDS 



Mammals : 



2, Mammut americanum, jaw with 4 teeth (see ibid., plate 25, fig- 

 ure 2y. 



4. Elephas (?), part of humerus (see ibid., plate 25, figure 4). 



6. Elephas imperator (?), femur, 4 feet, broken (see ibid., plate 25, 



figure 6). ^ 



7. Elephas imperator, sixth molar (see ibid., plate 24). 

 9. Elephas (?), scapula, fragment. 



157. Limb bone of proboscidian. 

 18 (a). Rib, unidentified. 



56. Camel, first phalanx (see ibid., plate 21, figure 1, and plate 22, 

 figure 2). 



66. Equus , acetabulum. 



84. Equus , part of metapodial. 



Mollusks : 



Sphmrium sulcatum. 



15. Wallace pit. — This is a sand and gravel pit in the bluffs of the 

 Little Sioux (which are also the east bluffs of the Missouri Valley) near 

 the north line of section 31^ township 81 north, range xlv west. Here the 

 Aftonian rises to 35 feet above the valley. The lower part of the section 

 was obscured by a talus, but coarse sand, with some gravel, rises distinctly 

 to a height of 20 feet above the valley. Then follows a stratum of mixed 

 and alternating yellow silt and sand for 15 feet. Above this the Kansan 

 is about 10 feet thick, the Loveland 6 to 8 feet, and on the hill above the 

 section the loess rises to the summit. 



The Aftonian is typical. Mr. Wallace opened a pit in the same bluff at 

 a point about 60 yards south, and exposed 16 to 18 feet of gravel. The 

 present pit shows sand chiefly. In this fragments of a TJnio, or related 

 mussel, were found. 



16. Robinson pit. — It is located in the southw^est quarter of section 16, 

 township 80 north, range xliv west, and is a tj^pical Aftonian section, with 

 Kansan drift and Lovfeland and loess above. The Aftonian rises to a 

 height of about 40 feet above the valley, and is sharply separated from the 

 Kansan by an oxidized band and by large nodular calcareous plates. It 

 contains very little silt, but is made up chiefly of sand and gravel of the 

 characteristic type. 



The following mollusks were collected in the sand: 



Unio , fragmthts of thick- Lymncea reflexa. 



shelled specie*^. Segmentina armigera. 



Sphwrium sulcatum.. Polygyra , fragments of a 



Pisidium . large species. 



Valvata tricarinata. Vitrea Tiam.monis. 



Bythinella oMusa. Succinea ovalis. 

 PlanorMs parvus. 



