[Annals N. Y. Academy of Sciences. Vol. XX, No. .3. Part II. pp. 189-238. 



26 October, 1910] 



NEW GENERA AND SPECIES OF CAEBONIFEEOUS FOSSILS 

 FEOM THE FAYETTEA^LLE SHALE OF AEKAXSAS^ 



By George H. Girty 



(Presented by title before the Academy, 3 October, 1910) 



The Fayetteville shale is named from its occurrence about Fayetteville 

 in northwestern Arkansas. Its character and distribution in this region 

 are described in detail in the Fayetteville folio,^ and only a brief sum- 

 mary will be given here. It is a black, fissile shale containing beds of 

 sandstone and thin limestone, and, in the southeastern part of the Fay- 

 etteville quadrangle, it attains a thickness of 200 feet, owing to the de- 

 velopment of a sandstone member in its middle portion. The shale rests 

 either directly on the eroded surface of the Boone formation or on some 

 sandy strata of sporadic occurrence which have been correlated with the 

 Batesville sandstone. 



The more or less impure limestones of the Fayetteville contain abun- 

 dant fossils. A rather persistent calcareous bed at the very base of the 

 formation has furnished the new species described below, except for a 

 very few w^hich came from a locality in the Batesville sandstone near the 

 town of Fayetteville. This collection from the Batesville shows, as would 

 be expected, a close relationship with the fauna whose horizon is just 

 above, (ieographicall}^, most of the collections studied came from the 

 Fayette^ille quadrangle, but a few were obtained beyond its borders, 

 where the tj^pical character and relationship of the formations are main- 

 tained. 



The Fayetteville shale has usually been referred to the horizon of the 

 St. Louis limestone. A discussion of this point is deferred until the 

 entire fauna of the Fayetteville has been studied. 



Michelinia meekana sp. nov. 



Zoarinm lenticular, attaining a large size, about 85 mm. in diameter and 

 4.5 mm. in thickness, more or less. Upper surface irregular. Coralites very 

 variable in size: the large ones reach a diameter of 7 mm., but very few are 

 of this size. The rudimentary septa consist of fine ridges, more distinct m 



1 Published by permission of the Director of the United States Geological Survey. 

 = !'. S. Geol. Survey. Folio 119. 1005. 



(189) 



