

across Mississippi, Louisiana, and Texas. 363 



Thus far, however, the facts gathered regarding them are not 

 sufficient in number, or they are not as yet well enough under- 

 stood, "to lead to any decided conclusions. In the northern 

 part of the state, in the Boston Mountains region, the faults are 

 nearly all normal or tension faults, while south of the Arkansas 

 river and in the Ouachita region they are reversed faults. The 

 one that lies nearest the Cretaceous border is the Red River 

 monoclinal fold which merges into a fault about its northern 

 end in the vicinity of Batesville. Here the downthrow is on 

 the southeast side and the displacement is 165 feet ;* at one 

 place it is more than 200 feet. In Stone county a fault on 

 Roasting-ear Creek has its downthrow of 100 feet on the 

 south; in Baxter county on Spring Creek is a downthrow of 

 between 200 and 300 feet on the south ; on Rush Creek, 

 Marion county, the downthrow is 260 feet on the south side ; 

 a fault about twelve miles long runs northeast from near St. 

 Joe having a downthrow of about 200 feet on the south side. 

 The St. Joe fault has its downthrow of 283 feet on the south. 

 On Big Buffalo Creek (16 K, 22 W., sees. 10-11) the down- 

 throw on the south is 400 feet. Many other similar cases 

 might be cited. It should be added, however, that there are 

 several faults in this same region having the downthrow on 

 the north side ; and there are some cases of long narrow strips 

 having sunk downward. The faults here mentioned are north 

 of the Boston mountains. South of the mountains we have 

 the Red River monocline turning westward and passing into a 

 great fault along the south face of the Boston mountains with 

 a downthrow of several hundred — perhaps a thousand — feet on 

 the south. 



On the south side of the Arkansas Yalley faults are known 

 with the downthrow on the north, but on this side of the 

 valley the faults are, in every case with which I am acquainted, 

 reversed faults. Three miles up the river from Little Rock, 

 at Big Eddy, are evidences of a reversed fault having the 

 north side underthrust. 



In the novaculite area through the Ouachita region but few 

 faults have been located with certainty ; ' the one mentioned 

 by Mr. Griswold in his report on novaculites has no reference 

 to the direction of the downthrow, f but the field-notes show 

 that it is on the south side. The novaculite region as a whole 

 has the beds pretty closely squeezed, and it is quite probable 

 that instead of a few large faults it has a great many small 

 ones. 



Dr. ~N. F. Drake, who has lately studied the geology of the 

 Indian Territory, tells me that the rule for Arkansas faults 



* Ann. Rep Geol. Sur. Arkansas, 1890, vol. i, 111, 220. 

 f Ann. Rep. Geol. Sur. Arkansas, 1890, iii, 295. 



