STRATIGRAPHIC TAXONOMY 055 



sponds to Division E. In fact, the harmony in lithologic characters 

 between these parts of the formation in the two areas is greater than 

 may appear from the descriptions. This correlation is borne out by the 

 already suggested relations of the third division and the lower part of the 

 fourth to the Fort Cassin limestone. 



The Beekmantown hettueen Carlisle and Alleniown. — Tracing the Beek- 

 mantown in a northeasterly direction from Chambersburg, it is found 

 to hold nearly the same characters and thickness, at least as far as 

 Carlisle. Here both the Stonehenge member and the overlying cherty 

 Cryptozoon steeli zone, constituting the lower third of the whole, are 

 clearly recognizable. The middle divisions maintain practically the same 

 lithologic characters as at Chambersburg, but the fossils have become 

 much rarer. The upper beds also are recognized v^fithout difficulty, espe- 

 cially the fossiliferous fifth division. This locality, finally, affords an- 

 other comparatively rich fossil zone in the uppermost division, comprising 

 species so far observed only here. 



Farther northeast, between Harrisburg and Lebanon, only the middle 

 and lower parts of the formation are to be seen. The top beds may 

 occur under the cover of Triassic sandstone, but are wanting on the ex- 

 posed Beekmantown. These rocks being thrust northwestwardly over 

 the Martinsburg shale, it is possible that such elevated parts of the 

 Beekmantown were largely cut away by erosion prior to the deposition 

 of the Mesozoic sandstones. In that case the upper divisions, if present 

 originally, may have been removed. 



The lower and middle divisions of the Beekmantown are still easily 

 recognized to the north of Reading along the Pennsylvania Railroad 

 between Ontelaunee station and Leesport. Apparently the upper divis- 

 ions (third to sixth) of the Chambersburg belt were not deposited here; 

 and the same reason probably explains their absence between Lebanon 

 and Harrisburg. 



In the Lehigh Valley of Pennsylvania the Beekmantown is repre- 

 sented by the same members (lower and middle) as at Leesport, but 

 locally, as at Ironton, beds are found with the Ceratopea fauna which 

 is found in the third division of the Beekmantown at Chambersburg, and 

 is thought to be represented in the lower part of the Axeman limestone 

 or the top of the Nittany dolomite in the Bellefonte section. The Cera- 

 topea fauna occurs perhaps, in this valley, only locally at the top of 

 the section. In a recent letter Prof. B. L. Miller and Mr. E. T. Wherry 

 suggest the name Coplay limestone for the Beekmantown as developed 

 in the Lehigh Valley. T am incline^l to regard the proposition favorably. 



