252 TRANSACTION'S OF THE [maR. 15, 



preserved specimens in the United States Geoloo:ical Survey 

 collection in the hands of Professor Williams, and these have 

 been kindly loaned for illustration. 



Heretofore little or no effort has been made toward a determi- 

 nation of the exact equivalents, in the typical Mississippian sec- 

 tion, of the formations of the same series in northern Arkansas. 

 The base of the series has been generall}' recognized b}' the Ar- 

 kansas geologists, as has also been the Millstone Grit or basal 

 conglomerate of the coal measure series. The intermediate for- 

 mations have been more or less thoroughly- described lithologi- 

 cally and have been given local names, but the results of thor- 

 ough investigations of the successive fossil faunas, have vet to 

 be published. The importance, for the correlation of the whole 

 series, of definitel}' fixing the horizon of some midwav stratum 

 in the series, can readily be recognized. 



The Batesville sandstone is an easily recognized formation 

 at about the middle of the series, and it has been selected for 

 a more detailed stud}', with special reference to its exact corre- 

 lation with the formations of the tjn^ical Mississippian section. 

 The formation is well developed in the region of Batesville in 

 Independence count}', from which town it takes its name. It is 

 a light 3'ellow or buff colored rock, sometimes shading into a 

 deep brown ; fine grained and homogeneous in texture, generally 

 hard and sometimes slightly micaceous. The greater portion of 

 the formation is heav}' bedded and hard, though it is more 

 thinly bedded and softer near the base. It is used extensively 

 for building purposes in Batesville, where there are large 

 quarries. In some localities the sandstone is interbedded with 

 lenticular layers of dark shale which are sometimes of consider- 

 able extent. 



Fossils are abundant in the lowermost, softer layers of the 

 sandstone, but in the dense, higher beds they are entirelj' alisent. 

 The collections upon which the present study is based are from 

 two localities. The first and most important localit}' is at 

 Ramsej^'s Ferry, about one-half mile southeast of Batesville. 

 The fossiliferous beds found here are situated on the north bank 

 of White river, just east of a small guile}' a few rods east of the 

 ford. The greater number of species were secured from this 

 place, where they occur in the better state of preservation. The 

 second locality is along the White river branch of the St. L. I. 

 M. & S. R. R., near Spring creek, about two miles west of 

 Batesville. At several points the railroad cuts into the sand- 

 stone. For half a mile the track is ballasted with the broken 

 sandstone, and most of the fossils from the locality were secured 

 from these broken masses. 



