FAUNAS OF DEVONIAN SECTION NEAR ALTOONA 635 



This assemblage of species is a representative Chemung fauna, 

 and does not differ notably from the Chemung facies as developed 

 at the type locality on the Chemung River. Like the latter, it includes 

 Spirijer mesastrialis, and some other forms vi^hich come up from 

 lower horizons, in association with such characteristic Chemung 

 forms as Spirijer disjunctus, Dalmanella tioga, and Stropheodonta 

 mucronata. These three species may be considered pre-eminently 

 characteristic of the Chemung. Their appearance in the sections is 

 coincident with the advent of the Chemung fauna in the Allegheny 

 province, and they remain throughout its stay in the region. In a 

 recent publication^ it is stated that Spirijer disjunctus does not 

 appear in the sections till the "period of Chemung deposition was 

 well-nigh over." The writer, however, has collected this species in 

 one of the sections included in the above-mentioned report, 200 feet 

 below the base of the Chemung, as drawn on the map which accom- 

 panies it. It occurs also very near the base of the Chemung fauna 

 to the northeast of the area discussed in the paper. The faunas, 

 therefore, appear very clearly to controvert the statement in question 

 Although Spirijer disjunctus is frequently a rare species in the lower 

 part of the Chemung, as it often is in the upper part, the writer's 

 observations indicate that it is generally present at or near the base 

 of the Chemung in some of the sections of any given area, and that 

 the earliest appearance of the Chemung fauna is generally coincident 

 with the advent of Spirijer disjunctus southwest of Altoona. In a 

 section near Queen, southwest of the Altoona section, this species 

 occurs near the base of the Chemung. In the Virginia sections it 

 occurs inthe lower Chemung, as it does in New York. 



I Bulletin No. 81, New York State Museum, p. 21. 



