2 PP. REPORT OF PROGRESS. FONTAINE & WniTE. 



These had been previously numbered by them X (Ves- 

 pertine), XI (Umbral), XII (Conglomerate) and XIII (Coal 

 Measures.) 



In the Reports of Progress of the Second Survey of Penn- 

 sylvania the following names have been employed: — Po- 

 cono Sandstone (X), Mountain Limestone, Mauch Chunk 

 Red Shales (XI), Pottsville Conglomerate (XII), Coal Meas- 

 ures (XIII.) 



Where the Catskill (IX) or "Old Red Sandstone" of 

 the English Geologists is found, it is capped by the Vesper- 

 tine, but where it is wanting, the Vespertine succeeds the 

 Chemung (VIII.) 



The Vespertine forms a well marked horizon, including 

 the oldest of the strata of Carboniferous age. The Umbral, 

 or No. XI of the old surveys, includes two very different 

 series. The lower portion is a great limestone, correspond- 

 ing to the "Mountain," or "Lower Carboniferous Lime- 

 stone," of European G-eologists. The upper portion is, 

 along the eastern border of the Virginia field, a mass of 

 shales and sandstones, mostly red. Owing to the fact, that 

 in Pennsylvania, the limestone thins out, and gives place 

 to a great mass of shales and sandstones, some geologists 

 class the limestone as a member of the Umbral Group. 

 As, however, in West Virginia, the limestone is in great 

 force, and is well distinguished from the overlying sand- 

 stones and shales, and as it is identified with a world-wide 

 formation, we will place it as an independent member, in 

 the grand divisions. 



The Productive Coal Measures are found to be naturally 

 divided into four well marked groups, two yielding work- 

 able beds of coal, and two, which are almost devoid of 

 persistent workable coal beds. Accordingly, the fifth divi- 

 sion above named, or the Productive Coal Measures, has 

 been sub-divided into {a) The Lower Productive Measures, 

 (6) The Lower Barren Measures, {c) The Upper Productive 

 Measures, id) The Upper Barren Measures. 



In this sketch of the general geology of our field, we do 

 not pretend to give the reader anything more than a mere 

 outline, sufficient to enable one not familiar with the order 



