STRATIGRAPHIC TAXONOMY 659 



Foet 



1. Rather massive limestone, some ledges nearly pure, others evi- 

 dently somewhat magnesian, and many with "edgewise 

 conglomerate ;" 12 feet beneath top a ledge full of the small 

 gastropod (cf. Ophileta levata) noted in bed 3. Exposed 

 opposite gate to Nittany furnace 35 



Total thickness of Stonehenge limestone ^* 662 



Total thickness of Canadian in the Bellefonte section about 4,232 

 Break 



Top of Kittatinny formation, of which about 340 feet are ex- 

 posed in the axis of the anticline as seen along Logan 

 Branch of Spring Creek. The boundary between the Ozark- 

 ian and Canadian rocks is drawn at the altrni)t cliaiige 

 from the dolomites of the former to the pure (Stonehenge) 

 limestone formation at the base of the latter. The contact 

 is fairly well shown along the road opposite the Nittany 

 furnace. 



The above section is repeated, but not so well shown in the 

 east limb of the anticline. 



Correlated with Canadian formations in other areas an analysis of 

 the fossil zones in the above section leads to interesting and somewhat 

 surprising results. The lowest of the fonr formations is correlated with 

 the Stonehenge member constituting the lower 400 to over 700 feet of 

 the Beekmantown in the Chambersburg and Mercersburg, Pennsylvania, 

 quadrangles. Good fossils are exceedingly rare in the typical outcrops 

 of the Stonehenge near Chambersburg, but so far as collected they offer 

 no serious objection to being placed in essential contemporaneity with 

 those found in the lower limestone division of the Canadic at Bellefonte. 

 An orthid like DalmanelJa wemplei occurs, with the new Asaphus and 

 small Ophileta levataAike gastropods, also at Chambersburg. At both 

 Chambersburg and Mercersburg the Stonehenge consists of alternating 

 beds of calcareo-argillaceous, slightly magnesian rock and massive, nearly 

 pure limestone. At both localities, again, these are overlain by cherty 

 beds, which, in turn, are succeeded by heavy-bedded limestone in the 

 Chambersburg area. However, in the exposures of Beekmantown lime- 

 stone near Mercersburg, where the Beekmantown has a total thickness 

 of 2,370 feet, much the greater part of the formation above the 680 



»* The corresponding beds in Collie's section have an aggregate thickness of 894 feet. 

 This estimate is I believe excessive, and possibly due to error in transcribing field notes. 

 The second "brecciated" bed. No. 7 of his section (op. cit., p. 411), was not observed. 

 Possibly it is the same as his No. 3. 



