PEALE.] 



GEOLOGY SECTION NO. 1. 195 



evidently deposited in shallow water and near a shoreline. The angle 

 of inclination is about 65°, and the dip is north 65° east. 



Above, the sandstones soon become uniformly red in color and some- 

 what finer grained. 



Fig. 1, Plate I shows the beds on the north side of the river, their 

 relations being exactly the same as on the south side, where the section 

 was made. 



The following is the section : 



Section iVb. 1, 07i south side of South Platte Biver. 



In descending order : 



^. j 1. Fine-grained white limestone, with crossfracture ^ 



'■ ( 2. Gray limestone, (fossiliferous) > 600(?}feet. 



Cretaceous Xo. 2*h. 3. Space covered up. ) 



I C 4. Gray and yellow sandstones, 70 feet ] 



l^-J 5. Shaiy sandstones, (fossiliferous,) 12 feet- | 



I ° I 6. Fine-grained white sandstone, 3 feet } 930 feet. 



^ ( 7. Eusty, yellow sandstones, 245 feet | 



[ 8. Space covered up, estimated 600 feet ... . \ 



« { 9. White arenaceous limestone, 5 feet "J 



>? ^ J 10. Pink calcareous limestone shales ) .r fpp^- I 



;fs "^ 11. Arenaceous and pebbly limestone ) "^ } 150 feet. . . 



I 12. Space covered up ) . j.^ P , | 



^" [ 13. Compact red limestone K^" ^^^^ 3 



-e ^ C 14. White sandstone with red bauds 600 feet. 



-si J 15. Space covered up > 1 500 feet to '> 000 



;!l i 16. Eed sandstones \ "^'^^^ y^}^ '^''^"" 



^^ (^17. Coarse white and red mottled sandstones. ) ^^ * 



*a. 18. Granite. 



The thicknesses in this section are for the most part estimated. The 

 letters correspond with those in Fig. 1. Beds 14 to 17 will still have to 

 be considered as Triassic (?) both from their general character and their 

 position. Although there are exposures of these red sandstones all 

 aloDg the edge of the foot-hills from Denver southward, I could find in 

 them no fossils, even after the most careful search. They are for the 

 most part .so coarse in their texture as to be unfavorable for the preser- 

 vation of animal remains. The space No. 15 in the section is, in all 

 probability, filled with red sandstone, of which No. 16 is the continua- 

 tion. In No. 14, the white portions are somewhat conglomeritic, while 

 the red bands are fine grained and calcareous. The red bands vary in 

 thickness from 4 feet to 6 feet, while the others are 20 feet to 30 feet at this 

 place. As we go south, however, we find that these sandstones are very 

 irregular in structure. No. 13 is a blood-red limestone, somewhat irreg- 

 ular in structure, but very hard. Although it contains no fossils, I am 

 inclined to consider it, together with beds 9, 10, and 11, as of Jurassic 

 age. Space No. 12 is filled most likely with limestones, while in space 

 No. 8 we have at the top greenish shales passing down into limestones 

 with the gypsum bed, as seen in some of the sections made farther 

 south. The pink calcareous shales (No. 10) pass gradually into the 

 limestones (No. 11) in which there are large flinty pebbles. All the 

 beds covered up in space 8 are probably Jurassic. That these beds 

 from No. 8 down to No. 13, inclusive, should be referred to that age, is, 

 I think, scarcely to be doubted, not only from their position, but also 



* The letters given iu tlie sections refer to tlio illuetrations. 



