310 Notice of the Anthracite Region in the 



1. A rock composed of fragments or ruins of other rocks, the 

 parts and cement of which are principally siliceous ; the fragments 

 are of various size, from that of pebbles to that of sand ; in the latter 

 case the mass is called sandstone ; in the former, puddingstone; oth- 

 er names might be mentioned, but these are sufficient ; most geolo- 

 gists, however, will call this series of rocks grauwacke ; and when 

 they are slaty in their structure, they obtain the name of grauwacke 

 slate. They are usually referred to the transition class. 



2. Argillaceous slate, in many varieties of fineness and firmness, 

 and often abounding with vegetable impressions, which are found 

 also, but more sparingly in the siliceous rock. 



3. Anthracite coal, in regular strata, between roof and pavement. 

 This simple arrangement of three members in the series, appears 



to embrace all that is essential in the construction of the valley j I 

 omit, of course, accidental rocks and unimportant varieties. 



The usual roof and floor of the coal is clay slate ; but some- 

 times the sandstone lies directly upon the coal, the slate being omit- 

 ed, and not unfrequently, when the coal is near the top of the 

 ground, both rocks are absent, having probably been removed, ei- 

 ther by violent causes, or decomposed by time, into loose earth ; in 

 such cases, the coal and slate, in a state of minute division, are usu- 

 ally mixed with the earth, and even with the soil, which is thus ren- 

 dered more or less black, and frequently appears on the surface, in 

 what are locally called, coal blossoms. 



The inclination of the strata varies, generally, between four de- 

 grees and fifteen or twenty, but it occasionally becomes much great- 

 er and is in some few instances nearly perpendicular ; I have never 

 seen it quite so in this valley or quite horizontal. The direc- 

 tion of the strata is between N. and N. E. and S. and S. W. ; the 

 dip is generally towards the rivers, and of course it is opposite on 

 the opposite sides of the rivers ; on the eastern side, it declines to 

 the west, and on the western side to the east. 



The strata of particular mines, however, generally copy the form 

 of the upper surface, immediately over them ; they are therefore 

 sometimes curved, or irregular, or saddle- or mantle-shaped ; and I 

 saw one that was dome-shaped. 



Between Pittston ferry, at the junction of the Lackawanna and 

 Susquehanna, and Mill Creek just above Wilkesbarre, a distance of 

 eight or nine miles, on the eastern side of the river, the strata, imme- 

 diately on the river's bank, dip to the east, contrary to the inclination 



