EVIDENCE THAT BEDS ARE AFTONIAN . , 137 



A well located just opposite the dam and about 5 rods from the river 

 revealed the following: 



Loess, 



T , , ^ 23 feet. 

 Loveland, 



Aftonian : 



Colored sand, 4 feet. 



White sand, 5 feet. 



Coarse gravel, 2 feet. 

 Missourian limestone, penetrated 4 feet. 



The top of the well rises 39 feet above the dam. 



The third section is in a sand pit, excavated at the level of the road, 

 which is about 23 feet lower than the top of the well. 

 The following section was shown: 



Aftonian : 



Sand and finer gravel, 9 to 32 feet. 



Fine silt, about 1 foot. 



Coarse ferruginous gravel, 18 inches. 

 Missourian limestone. 



It will be noticed that the Kansan and N"ebraskan drifts are wanting 

 in all these sections, but the arrangement of the formations present is 

 consistent with the typical section. 



The lowest gravel bed is the only fossiliferous part of the Aftonian in 

 these sections. It yielded the following: 



Elephas columhi, a good molar, collected north of the middle of the 



quarry section. 

 Fragment of a large scapula (?), with the preceding. 

 Equus (?), a fragment, probably from limb bone of a horse, was taken 



from the well. 

 Part of a rib and a fragment of an unidentified bone were taken from 



the gravel in the sand pit. 



19. Denison pit, — This is a railway sand pit located near the northwest 

 corner of section 14, township 83 north, range xxxix west, near Denison, 

 Iowa. It is excavated in a detached knoll in the valley of the Boyer Eiver. 



The evidence that the sands and gravels in this pit are Aftonian is per- 

 haps less satisfacton^ than in any of the other sections discussed in this 

 paper; yet the preponderance of evidence favors their reference to that 

 period. 



The pit presents the following section :- • • - 



Loess, light, yellow or slightly brown stained, 2i^ feet. 

 Fine sand, laminated as in dune formation, 5 to 6 feet. 



X — Bull. Geol. Soc. Am., Vol. 21, 1909 



