VARIABLE GRADES OF THE OLD CHANNELS. 289 



Kentucky flat, and continued from there under the lava cap to a place 

 a short distance to the northeast of Volcanoville; at one intermediate 

 point, Missouri gulch, it is exposed for a short distance. 



Grades' : 



Jones hill (2,114 feet) to Floris (2,530 feet), 5] miles, 76 feet to the 

 mile. 



Floris to Volcanoville, 3 miles, 112 feet to the mile. 



Volcanoville to Missouri gulch, 2 miles, 114 feet to the mile. 



Missouri gulch to Kentucky flat, 2 miles, 62 feet to the mile. 



Jones hill to Peckham hill, 1\ miles, 57 feet to the mile. 



Peckham hill to Dardanelles, 5-i miles, 90 feet to the mile. 



Dardanelles to Mayflower, 2\ miles, 52 feet to the mile. 



Mayflower to Bath, 21 miles, 40 feet to the mile. 



The Iowa Uill Channel. — Difficulties also exist in connectino; the Iowa 

 hill channel with the rest of the drainage. I have assumed that a con- 

 nection existed hetween Indiana hill and Iowa hill, and that the Iowa 

 Hill channel ran southward and connected with the inlet at Yankee 

 Jim. One of the principal objections to this view is the occurrence of a 

 small gravel body at an intermediate point, Kings hill, which appears to 

 he about 70 feet lower down than the lowest bed-rock at Yankee Jim. The 

 Iowa hill or Morningstar channel, as it is also called, has been described 

 in detail by Mr Hobson,* who concludes that the stream had a grade 

 toward the north, and that coming from some point on the Forest Hill 

 divide it was joined north of Iowa hill by a tributary from Indiana, hill, 

 after which it curved westward and flowed down toward the plains along 

 the canyon excavated by the present stream. Mr Hobson's own figures 

 on the maps and the profiles accompanying the paper do not seem to 

 me to warrant this conclusion, as far as the grade is concerned. The 

 bed-rock south of Iowa hill and at the hydraulic workings of the Morn- 

 ingstar has exactly the same elevation, according to the figures on Mr 

 Hobson's map, as the starting point at the southern end of the covered 

 channel at Wisconsin hill, a distance of between two and three miles. 

 North of Iowa hill there is a sudden descent of some 50 or 60 feet, but 

 the distance in which this descent is accomplished is only one-fifteenth 

 part of the whole length of the channel; and it looks very much as if 

 this depression were caused by a slight fault, especially as there are two 

 or three of such disturbances shown on his profile in the Morningstar 

 ground. An examination of Mr Hobson's profiles will inevitably lead 

 to the conclusion that before the faulting, whether this took place by air 

 uplift of the southern side or a downthrow of the northern, there was a 



* Tenth Ann. Rep. State Mineralogist of California, p. 420. 

 XLIII— Bui.r,. Oeoi.. Soc. Am., Vol. 4 1892. 



