REPORT OF THE STATE PALEONTOLOGIST 1902 989 



such a pebbly bed may thicken into a locally prominent stratum 

 and become a source of perplexity and possible error in tracing 

 the stratigraphy if no near-by measure to a known horizon were 

 obtainable as a check. 



Fucoids. Fucoidal remains in the shape of vertical tubes 

 piercing the sandstone or conglomerate layers of the Salamanca 

 are specially characteristic of that horizon and in its north- 

 eastern portion were often used as an aid in its identification, 

 though in all cases of doubt reliance was placed in its inverte- 

 brate fauna. Southwestward in Warren county, Pa. while 

 vertical fucoidal remains are still often very prominent in the 

 Salamanca, they also occur at other horizons and hence if they 

 may be used at all in that region as an aid in identification, 

 it must be done only with a recognition of this fact in mind. 



COLUMNAR SECTIONS 



A few columnar sections selected at considerable intervals 

 over the region are added in order to give some idea of the 

 general stratigraphic succession in the region. They are ne- 

 cessarily generalized somewhat in the representation of thin 

 beds. The concealed intervals are in most cases almost cer- 

 tainly shales but in the sections are left blank. In section C 

 pieces of the Wolf creek were found loose on the surface up 

 to the level indicated by the displaced blocks, and the same 

 thing is true of the Salamanca in section E. The thickness of 

 the two thin limestone layers in the basal part of the Oswayo 

 in section F is much exaggerated. In some cases the interval 

 represented as being red shale consists of red and green shales 

 interbedded in very thin layers. The purple or chocolate col- 

 ored shale beds of the Chemung are seen in sections B and D. 

 Eastward from B the Salamanca conglomerate lenses out, and 

 in B the Subolean conglomerate — though probably not con- 

 glomeritic in this particular section — had been eroded before 

 the deposition of the Olean. 



Finally, the writer wishes the conclusions that have been 

 reached as to correlations in McKean and Warren counties to 

 be recognized as ones based on a reconnaissance in a region 

 where such work is beset with many difficulties. It is believed, 

 however, that detailed work will only confirm the conclusions 

 reached. 



