122 .1. tf. DILLEB — SANDSTONE DIKES 



:ui<1 the mica plates in them are all arranged parallel to the banding. Hand 

 specimen '2h"i shows the banding plainly. Section 2407 is from an appar- 

 ently coarser portion in the middle. Sere, too, are well seen the ripple-like 

 mark- upon the outer face of the dike. They have been seen elsewhere. 

 especially al J s . on Salt creek, and will be referred to again. Near the 

 same place may be Been a small dike offsetting mice to the eastward. The 

 offsetting portions are not visibly connected. 



Continuing up the stream, a 14-inch vein and several smaller ones may 

 be observed before reaching John Allen'.-, three miles above the mouth of 

 of Salt creek, At this point 12) Beveral dikes occur in the left bank of the 

 stream. One dike is <> and another 4 inches in diameter, and these may he 

 seen again a short distance to the uortheasl in Horse gulch, which opens into 

 Dry creek at Allen's. One of these dikes, with a very small one near it, is 

 displaced above to the eastward. Hen-, also, three small veins combine as 

 they ascend and form a larger one. 



One-fourth of a mile above John Allen- is a L4-iuch dike, which in a 

 high hank cuts fit'ty feet of exposed -hale and can be traced across the bed 

 of the stream and into the field for several hundred yards. Specimen 1963 

 i- from this dike. Near by are several other small dike-. 



At 44, five and a half miles above the mouth of Salt creek, two prominent 

 dikes are exposed in the left hank of the stream. One is 18 inches in thick- 

 ness ami quite irregular, a- shown in 6g. I. An offset occurs in the dike 

 near the base ot' the bluff, and it contains fragments of -hale. This dike 

 appear- to he approximately in line wjth the Great dike, which was la-t seen 

 on Middle fork. With this extension the Great dike has a total length of 

 about '.i. 1 ; mile-. 



A few yards up si ream another dike occurs, 1 ■'! inches in thickness : strike 

 \. :;i E. ; dip 75 N. W. Near its edge tin- dike contains numerous frag- 

 ments of shale. Specimen 2400 contain.- fragments of the shale, and specimen 

 2401 is from the middle of the dike. Several small dikes have been ob- 

 served further up Dry creek. They are marly in line with some of those 

 exposed on Middle fork ami Berve to join all the dikes together in one large 

 group. 



Dikes of Fight Gulch. — South of Dry creek, the dike- are oexl exposed 

 in Fight gulch, which open- from the northwestward into Salt creek about 



two and a half mile.- above it- mouth. At I"), a 2-foot vertical dike occur-, 

 with a -t like of N. 38 E. The 'like rock contains a few fragments of -hale. 



and is full of mica which lie- parallel to the sides of the dike. The sides of 



tie' dike have ripple-like marks which are nearly horizontal. 



< >ne hundred yards further down the gulch is a dike 3 feet in thickness, 



full of mica a- the other, ami with tie- -ame strike. \. \t comes a 15 inch 

 dike ; .-Hike N. 15 E. It i- W'll joiuted, ami ha a -mall parallel dike close 



