160 APPENDIX D. GEOLOGY. 



May 5. — For the first six miles the surface became gradually more 

 elevated. Here, and elsewhere to-day, we met with a number of hori- 

 zontal layers of coarse-grained and highly ferruginous sandstone, which 

 was more or less laminated, and highly embossed with ripple-marks. 

 In many places we met with extensive deposites of porous and dark- 

 colored igneous rock, containing a large per-centage of oxide of iron. 

 The surface was everywhere strewn with drift, mostly composed of 

 quartz, greenstone porphyry, and granite. Saw a number of conical 

 hills, varying in height from ten to seventy-five feet, and composed of 

 horizontal layers of sandstone, of. the same character as that first met 

 with to-day. Owing to the rapid disintegration of the sandstone, the 

 hills are gradually crumbling away. In many places we found a few 

 loose fragments of sandstone, intermixed with sand, the only indication 

 left of the previous existence of many of them. In this manner has a 

 levelling process gone on for ages, which, if not interfered with, will 

 ultimately tend to the removal of the various inequalities of the surface 

 of the prairies. Soil good ; subsoil argillaceous, and of a deep -red color: 

 this mixing in the form of sediment with the water, imparts to it a red 

 color and disagreeable taste. From the north branch of the Witchita I 

 collected a number of bivalve shells of the genus JJnio. 



May 6. — Sandstone and drift the same, as yesterday. Saw a num- 

 ber of bluff banks, varying in height from ten to fifty feet. They were 

 composed of red loam, the relative position of which was found to be 

 below that of the sandstone. Soil and subsoil the same as we passed 

 yesterday. 



May 7. — Formation the same. Drift appears to be gradually becom- 

 ing more abundant. 



May 8. — During the day we had frequent opportunities of observing 

 the sandstone and red loam. Their relative positions were the same as 

 before, and dipped in various directions at angles of from one to three 

 degrees. Saw a number of small boulders, composed of granite and 

 greenstone porphyry. 



May 9. — Did not move from camp. In the afternoon I explored a 

 few miles along the banks of the Big Witchita. The geological forma- 

 tion, as there developed, consisted of finely laminated, soft, ferruginous 

 sandstone, interstratified with red clay, together with drift, which last 

 was much coarser than any previously observed. Soil good ; subsoil 

 loamy. 



May 11. — Formation the same as before. Found a number of spe- 

 cimens of peroxide of iron. 



