552 .C. .N. GOULD CRYSTALLINE EOCKS OF THE PLAINS 



1917, happening to mention the fact to some business men of Amarillo, 

 their interest was aroused, with the result that the region was revisited 

 and a careful survey made of the largest of these structures, the John 

 Eay Dome, in Potter and Moore counties, some 20 to 30 miles north of 

 Amarillo. It was found that this dome had an area of over TOO square 

 miles, with a lift of about 500 feet. The first well drilled on this struc- 

 ture encountered gas, and since that time about a dozen gas wells have 

 been drilled on this dome, producing up to 107,000,000 cubic feet of gas 

 daily. Wells drilled on the 6666 dome in Carson and Hutchinson coun- 

 ties have produced both gas and oil. Other domes have proved to be 

 nonproductive. 



One very interesting thing about these structures is that as more and 

 more wells have been drilled we have learned that they are superimposed 

 upon buried crystalline rocks. The greater number of the wells reacli 

 either an arkosic sand or felsite, somewhere between 2,000 and 3,000 feet, 

 and at least two wells on each of the three domes — Bravo, John Eay, and 

 6666 — appear to have penetrated solid granite. 



Xow, by projecting the main axis of the Arbuckle-Wichita uplift to 

 the northwest, it will be seen that these domes are practically in line witli 

 this projection; also, there are four granite wells in southwestern Okla- 

 homa and the eastern part of the Panhandle, making in all ten granite 

 wells in practically a straight line with the Arbuckle-Wichita axis.-^ In 

 the light of present knowledge, therefore, it would seem safe to postulate 

 a buried granite ridge extending from the west end of tlie Wichitas north- 

 westward for a distance of at least 200 miles. 



In this connection it may not be amiss to call attention to tlie fact that 

 granite has been encountered in wells near Caney, Oklahoma, southeast 

 of the Arbuckle granite. It has been suggested that the Arbuckles, and 

 possibly the Wichitas, are connected with Llanoria.-'' At any rate, the 

 line along Avhich crystalline rocks, either surface or subsurface, occur 

 extends from southeastern Oklahoma, along the axis of tlie Arbuckle and 

 Wichita Mountains, and entirely across the Panhandle of Texas, as far 

 as northeastern New Mexico, a distance of nearly -100 miles. 



If a name be desired for this buried mountain range northwest of the 

 Wichitas, perhaps none better can be fomid than the name '^\marillo 

 Mountains." Powers has already used the term ''Amarillo Hills'' to 

 describe the buried structures under the oil- and gas-producing structures 

 in this region,-*^ but he did not include the gap between the 66{)C) dome 

 in Carson County, Texas, and the Wichitas. 



