abstracts: geology 605 



tinctly different from the typical Boone fauna and lithology, but these 

 cherty beds appear to occupy the same place in the section as the Boone 

 which farther west, as at Marshall, immediately underlies the Moore- 

 field shale; furthermore, in western Tennessee, there are dark shales 

 which must be of about the same geologic age as the Boone but which 

 contain a fauna having many features in common with the "Spring 

 Creek" limestone fauna. This broad and very interesting problem is 

 as yet unsettled. A conclusion so far as the cherty beds at Batesville 

 are concerned rests partly on the thickness and faunal content of some 

 light gray crystalline limestones that underlie the cherts in ques- 

 tion. They are almost certainly of Carboniferous age, but are as yet 

 uninvestigated. G. H. G. 



GEOLOGY. — The faunas of the Boone limesione at St. Joe, Ark. G. H. 

 GiRTY. U.S. Geol. Survey Bull. 598. Pp. 50, with 3 plates. 1915. 



This short bulletin consists of two parts, one describing the fauna 

 of the St. Joe limestone member of the Boone limestone, the other 

 describing a small fauna obtained in the Boone not far above the St. 

 Joe. The collections described in both papers were obtained near St. 

 Joe in northern Arkansas. 



The St. Joe limestone comprises about 30 feet at the base of the 

 Boone limestone and though composed of much the same materials, it 

 is faunally and lithologically a rather distinct and widely recognizable 

 unit. Except for some shaly beds of inconsiderable thickness below, 

 these limestones of the St. Joe are the earliest deposits of Carbonifer- 

 ous age in this region. The fossils described in this report, which 

 obviously represent the typical St. Joe fauna, comprise 30 species, some 

 of which are new. The fauna, though differing in certain respects, 

 strongly resembles the Fern Glen fauna of northeastern Missouri, 

 thus corroborating a correlation suggested by Professor Weller on rather 

 incomplete evidence. Weller's correlation of the Fern Glen and Chou- 

 teau is also agreed to in this report, ])ut it is suggested, though not 

 stated as a conclusion, that the Chouteau may really correlate with the 

 lower part of the Burlington limestone instead of being entirely older, 

 as commonly held. 



The small but interesting fauna from the Boone, just above the St. 

 Joe member, comprises 32 species, many of which are new. It is 

 noteworthy that this fauna indicates a great change in the organic 

 sequence following St. Joe time. The succeeding fauna does not pos- 

 sess either a distinctive Burlington or a distinctive Keokuk facies but 

 differs markedly from both. G. H. G. 



