220 C. S. Prosser — Devonian System, etc. 



"White's Montrose shale to the Honesdale sandstones, as ex- 

 posed along the D. L. & W. R.R, occurs the highest fauna 

 that has yet been found in Monroe and Pike counties. Above 

 these shells no fossils were seen in the higher rocks, except 

 undeterminable fragments of plants. The shells occur in 

 some greenish, argillaceous shales, about one and one-half feet 

 above red shales, at the northern end of the second railroad 

 cut north of Henry ville. Several good specimens of Spirifera 

 mesastrialis Hall were found and one of Leda diversa Hall (?). 

 Spirifera mesastrialis which is reported from the Hamilton of 

 Schoharie county, New York,* is an abundant and well known 

 species of the middle zone of the "Ithaca group " at Ithaca 

 and is also found in the lower Chemung farther south in 

 southern central New Yorkf and northern Pennsylvania,:}; 

 while Leda diversa is a Hamilton species of eastern and cen- 

 tral New Yoi'k. The fossils seem to indicate that these shales 

 are hardly younger than the lower Chemung and they might 

 be still older, since the specimens of Spirifera mesastrialis do 

 not appear to be the variety which is found in the lower 

 Chemung of southern New York ; but on the contrary the 

 form found in the older rocks of the Portage. The nearest 

 correlation to the above is that of Professor Stevenson in his 

 Vice-Presidential address before Section E of the American 

 Association, in 1891, when he drew the line, separating the 

 Catskill from the Chemung, between the Montrose sandstone 

 above and the Montrose red shale below,§ which is at a part of 

 the series not distant from the horizon in which the Spiriferas 

 were collected above Henryville. 



Above this horizon coarse, gray sandstones and shales alter- 

 nate with reddish shales. A thick mass of the red shale is 

 well exposed in the railroad cut just west of Oakland. The 

 cut below Mt. Pocono shows coarse, gray sandstone with frag- 

 ments of fossil plants, thin, bluish, argillaceous shales, breccia 

 and red shales, while in places the coarse gray sandstone con- 

 tains quartz pebbles and is probably near the horizon of Pro- 

 fesssor White's Cherry Ridge conglomerate, about 500 feet 

 below the top of the Catskill. || In general structure and 

 lithologic appearance, these rocks are very similar to the typ- 

 ical Catskill of the Catskill Mountains. 



On the summit of the Pocono plateau, about two and one- 

 half miles north of Tobyhanna, is a massive conglomerate 

 which is considered by Professor White as the Mt. Pleasant 

 conglomerate at the base of the Pocono. ^[ 



* Geol. Surv X. Y., Palaeontology, vol iv, Pt. T, p. 417. 



t Bull. U S. Geol. Surv.. No 3, pp. 17. 22, 24. 



% Proc. Am. Assoc. Adv. Science, vol. xxxiv, p. 231. 



§ Am. Geol.. vol. ix. p. 14. || G 6 , p. 78. foot note. 



IT G 6 , pp. SO, 329. 



