170 APPENDIX D. GEOLOGY. 



colored porous sandstone. Observed no drift to-day. Soil dark and 

 fertile ; subsoil argillaceous. 



July 1 0. — Formation the same as on yesterday. Soil dark and fertile ; 

 subsoil argillaceous. 



July 11. — Formation tbe same as before. 



July 12. — To-day we met with no gypsum. At about 9 o'clock we 

 came to Otter creek ; its bed is here, as well as elsewhere, composed of 

 finely laminated sandstone, containing small circular spots of a greenish 

 color. In many places this was covered to the depth of a few inches 

 with drift and detritus. Soil fertile ; subsoil argillaceous. 



July 14. — Renewed the observations of May 23d, 24th, 25th, 26th, 

 and 27th. 



July 15. — To-day we passed a number of the Witchita mountains, 

 but observed neither in their composition nor general appearance any- 

 thing different from what had been previously noticed. Near the base 

 of one of them I observed a nearly horizontal stratum of sandstone, 

 underlaid by red clay. The ground was in several places covered with 

 loose fragments of gypsum, some of which were found to contain slight 

 traces of copper. In one of the creeks I observed a small deposite of 

 black ferruginous sand. Soil black and fertile ; subsoil argillaceous. 



July 16. — The only difference presented by the mountains seen to- 

 day, from those previously observed, consisted in the greater number 

 and size of the quartz veins ; many of them were nearly perpendicular, 

 and extended from near the base of the mountains to their summits ; 

 while others, pursuing a more or less serpentine course, frequently inter- 

 sected each other at right-angles. The largest was highly ferruginous, 

 presented a more or less cellular structure, and was nearly three feet 

 wide. A few feet from the base of one of the mountains I observed a 

 horizontal stratum of coarsely laminated sandstone of a yellowish color, 

 and including in its composition small angular fragments of granite of 

 the same character as that of the neighboring mountains. To-day I 

 exanrned several of the head branches of Cache creek. Their beds 

 were thickly strewn with large angular fragments of quartz, greenstone, 

 and porphyry. In each of them I observed large quantities of black 

 ferruginous sand. Soil fertile ; subsoil argillaceous. 



July 17. — In a number of places the sandstone was exposed ; it did 

 not differ in character and composition from that seen the day before. 

 In one place the strata, still preserving their horizontal character, pre- 

 sented abruptly to the side of a mountain. Many of the mountains 

 presented a marked difference in character and composition from any 

 that had been previously observed : instead of displaying a rough and 



