INTERESTING LOCALITIES OF MESNARD QLTAKTZITE. 233 



with a strike in a nearly east-and-west direction and a, dip of al)out 80° to 

 the southward. While tlie slaty cleavage has a sti'ike approximately east 

 and west and a uniform southern dip, when carefully examined the bedding- 

 layers are seen to be in a series of sharply compressed anticlines and svn- 

 clines, with isoclinal southern dips and steep pitches. At certain places in 

 the gray slate or graywacke background are found numerous pebbles, some 

 several inches across, of red, felsitic-looking rock. These at first were 

 thought to be derived from an extraiieous source, but a careful examination 

 of all the ledges discloses every gradation between these pseudo-conglomer- 

 ates and the interlamiuated slate and red graywacke. During tlie intricate 

 folding the more rigid and brittle felsitic-looking graywacke was broken up; 

 the fragments were ground over one another and thus rounded; at tlie same 

 time they were buried in the slate and graywacke matrix. Step by step the 

 process may be traced from the phase in which the more resistant lavers are 

 merely shattered, through the phases in which the fragments are somewhat 

 separated but have a distinct linear an-angement corresponding to the 

 original la^er, to those ])hases in which no traces of the original coarser gray- 

 wacke layers as such are to be seen. In their places are the dynamically 

 rounded fragments in the slates. 



It is evident from tlie foregoing that this whole mass of slate and 

 graywacke has been kneaded in a most remarkable manner by the folding 

 process. Up to a certain point the accommodations have been luade by the 

 slipping of the layers over one another, with readjustment of the minor 

 particles within the layers, but in the most completely pseudo-conglomeratic 

 phase the jjseudo pebbles are so irregidarly distributed as to indicate that 

 the whole material must have been mashed together, the parallel layers 

 being compressed by the forces until the originally horizontal beds are in a 

 series of nearly vertical, isoclinal folds. 



Parallel to the schistose structure of the slates and graywackes, in 

 certain places, are veins and irregular oval lenses of impure ferriferous 

 dolomite. These are taken to be secondary infiltration or replacement 

 products. 



There are no continuous exposures connecting- the conglomerates on 

 the north side of the road with the slate on the south side, but there is little 



