392 STRATIGRAPHICAL GEOLOGY. 



In the south part of Lebanon the mica schists fold around the area of 

 Bethlehem gneiss, and in Fig. 6i we have a section illustrating the fact. 

 It begins on the west, with a hill of hornblende schist back of S. Water- 

 man's, dipping 50° N. 85° W. Next will come the continuation of argillo- 

 mica schists, believed to dip west. At A. Hall's and sons the argillaceous 

 matter predominates, dipping south-west, with conglomerates. Farther 

 south, near S. Wood's, are vertical layers of hornblende, with a course 

 north-south and N. 20° W. By O. S. Martin's the green, soft schists of 

 the Coos group appear, dipping 80° W. The same occur half a mile east. 

 The gneiss is not seen upon this road, as it does not extend so far south. 

 Its central line should strike by R. Wood's. The gneiss is visible from 

 the road upon the hill north, with a north-westerly dip ; and the outside 

 of the area corresponds with the upper layer of this rock, as observed 

 farther north in Lebanon and Hanover. Farther north, by F. Peabody's 

 and a school-house, the gneiss has the same position. The green schists 

 east of the axis, by L. Freeman's, dip north-west, and are very fully de- 

 veloped at J. Hebard's. About three fourths of a mile east of the gneiss, 

 the same mica schists dip north-west, and still farther east, 75° N. 35° W. 

 Where a north-south road crosses the east-west one, near W. and E. Kim- 

 ball's, the same rocks dip N. 25° W. This section illustrates, therefore, 

 a very clear case of inversion. The gneiss has a monoclinal, north-west- 

 erly dip, the same with that of the soft, green schists ; but the inclination 

 is steepest upon the west side. The force of compression has been so 

 great that one side of the anticlinal has been forced to dip in unison 

 with and beneath its opposite ; and the overturning has affected the Coos 

 schists as well as the gneiss. The hornblende does not appear to have 

 shared in the overturning, as it is not repeated on the east side; but its 

 course has been made to agree with that of the central axis. The curv- 

 ing of the newer schists around the gneiss is also illustrated in the strike 

 of N. 40° W. of the former at T. Wood's, half a mile south of O. S. Mar- 

 tin's. A north-west course is extremely rare in this vicinity, and its 

 occurrence here has an important significance. 



Coos Slates. We hope to distinguish several areas of slate from the 

 mica schists upon the map, partly because some portions of them are 

 with difficulty separated from the Cambrian series. It may prove here- 

 after that the distinction we have made is untenable ; hence their separa- 



