448 STRATIGRAPHICAL GEOLOGY. 



157, Indurated argillaceous schist. 178, Mica schist, coarsely crystalline. 



158, Mica schist, with staurolite. 179, Mica schist— pyritiferous. 



159, Indurated schist. Hinsdale— north of the village. 



160, 161, 161 a, Staurolite schist. 182,184, 186, 189-191, Staurolite mica 

 162, Clay slate — second road crossing the schist. 



state Jine. 183, 185, 187, Mica schist. 



Hinsdale — south of the village. 1S8, Argillaceous schist. 

 172, 173. Quartzite. Chesterfield. 



174, 175, 177, 180, 181, Mica schist. j^js, Granite, with plumose mica. 

 176, Staurolite schist. 



History of Exploration. 



This sketch will not be complete without extensive reference to the 

 writings of my predecessors in this field. The first notice of this lime- 

 stone I have seen in print is in the Report on the Geology, etc., of Massa- 

 chusetts, published by my father, in 1833, page 295. He says of it, — 



Since the first edition of the first part of my report was published, I have had the 

 satisfaction of discovering organic remains of the family of encrinites in the bed of 

 limestone in Bernardston. From the highly crystalline character of this rock, I had 

 been led to suppose it older than the encrinal or transition limestone ; and that it 

 formed a bed in the argillaceous slate, which appears to be one of the oldest varieties 

 of that rock. But its organic remains settle the question of its position ; and, differing 

 in dip and direction from the slate, 1 have been led to doubt whether it really forms a 

 bed in that rock. The slate in the vicinity runs more nearly north and south, and the 

 dip is nearly 90° ; but the limestone runs N. E. and S. W., and dips S. E. not more 

 than 20°, Besides, the rock that is found above the limestone appears to be mostly 

 composed of quartz, and probably ought to be called quartz rock. It does not lie in 

 immediate contact with the limestone, nor is the slate visible immediately beneath the 

 limestone. Upon the whole, I am of opinion that this limestone lies beneath the oldest 

 variety of the new red sandstone series, which has been described, and upon the argil- 

 laceous slate, in an uncomformable position. * * * * 



The encrinal remains in the Bernardston limestone are usually quite imperfect ; but 

 the transverse septa and the central perforation are generally distinct. Plate XIV, 

 Fig. 47, exhibits an end view of one encrinus, about an inch in diameter, and a view 

 of another lying horizontally in the rock. 



No additional facts respecting the limestone appear in the final report 

 of 1 84 1. It is noticed in a brief paper On the Geological Age of the Clay 

 Slate of the Connecticut Valley, in Massachusetts and Vermont, presented 

 to the American Association for the Advancement of Science, in 1851 (2 



