1886.] 327 [Crosby and Bavton. 



all the lower ground, and to some extent the higher slopes from 

 the conglomerate of ridge II to that of ridge VI. It has a steep 

 westerly dip at all points, probably underlying the conglomerate on 

 the west, and very clearly and conformably overlying it on the east. 

 The contact is well exposed on the west face of Hanging Rocks, 

 with several alternations of conglomerate and slate, showing a 

 gradual passage from the one to the other, as on Easton's Point. 



(3). Alternating with the slate in more or less regular bands, 

 and forming the main masses of ridges III, IV and V, we have the 

 third and most puzzling of the rocks of Paradise. It is a massive, 

 greenish, crystalline rock, showing to the naked eye an abundance 

 of chlorite (probably altered hornblende), iron oxide and feldspar. 



This is the "amphibolic aggregate" of President Hitchcock, and 

 the hornblende schist of Mr. Dale. All previous observers are 

 agreed that it is a highly crystalline stratified rock ; and its rela- 

 tions to the carboniferous strata have usually been explained as 

 due to a series of strike faults. Mr. Dale, regarding the slate as 

 also a crystalline rock, only requires two faults, as indicated in his 

 general section ; but Prof. N. S. Shaler, 1 referring the slate rightly, 

 as we think, to the carboniferous series, is obliged to bound every 

 band of the chloritic crystalline rock by two faults. 



After reading Mr. Dale's paper, and before visiting the localit}', 

 we felt that the geological interest of Paradise centred in the na- 

 ture and relations of this crystalline rock. Our first observations 

 caused us to suspect that it could not be a stratified rock, and we 

 were soon confirmed in this opinion. The rock is perfectly mas- 

 sive, showing absolutely no traces of bedding, but presenting just 

 the aspect of an altered though distinctly crystalline trap or green- 

 stone, and resembling many of the altered diabases of eastern Mas- 

 sachusetts. In proof of its eruptive nature we will present, first, 

 the purely lithological evidence. Mr. George P. Merrill, of the 

 U. S. National Museum, has kindly prepared and examined sections 

 of typical specimens from these crystalline masses. He reports : — 



"The rock is undoubtedly an eruptive ; but I am inclined to call 

 it diorite rather than diabase, although the alteration has been very 

 great and the silicates of iron and magnesia have been almost com- 

 pletely changed into the inevitable viridite and epidote. The re- 

 maining outlines are, however, plainly those of hornblende ; and 



* Am. Nat. VI, 616. 



