TERTIARY. 431 



In the Central Field the approximate and average dip is northwest seventy- 

 feet per mile. 



Millsap Division. 



This division only occurs in the Northern Field. The approximate and 

 average dip is northwest eighty feet per mile. 



Bend Division. 



This division occurs only in the Central Field. A general average was not 

 made, but the following measurements were made at the localities given: 



At five miles west of Lampasas Springs the dip is north 21-J- east one 

 hundred and five feet per mile. 



At Lampasas, north 30° east one hundred and five feet per mile. 



At Bend, north 23° west one hundred and fifty-eight feet per mile. 



At Cherokee Creek, north 84-J° east one hundred and fifty-eight feet per 

 mile. 



These last estimates were made on short distances, and are very much in 

 excess of what the strata would show on an entire section across the field. 



TERTIARY. 



BLANCO CANYON BEDS. 



Above the Triassic formation, and resting conformably upon conglomerate, 

 are the beds I have designated the Blanco Canyon Beds, which are possibly 

 the equivalent of the " Green River" Beds of Hayden. 



They constitute the upper beds of the Staked Plains, and are so well pre- 

 sented at Blanco Canyon that I have given this name provisionally to these 

 beds. 



They are composed of sands and clays. The clays and sands are indurated 

 in places until they are as solid as stone. Their thickness at this place is about 

 two hundred feet, with a gentle dip to the southeast. 



The following section was made of a hill at the foot of the Plains four miles 

 north of the town of Dockum. Beginning at the bottom : 



1. Reddish sandy clay , 150 feet. 



2. White clay (chalk) 4 feet. 



3. Purple clay 3 feet. 



4. White clay (chalk) 3 feet. 



5. White sandy clay 6 feet. 



Total 166 feet. 



This section rests directly upon those beds I have called "Triassic." From 

 the point where this section was made the Plains stretch away to an unknown 



