102 NEW YORK STATE MUSEUM 
walls, into which the dioritic, pegmatitic facies of the Pochuck has 
been intruded. 
c The rock-pendant. The rock which hangs from the roof of the 
east lobe is essentially the same material as that comprising the 
horse, but it has been soaked with the syenitic facies of the Pochuck, 
and modified to that extent; a modified Pochuck-Grenville, injected 
likewise with dioritic pegmatite, not greatly different from the horse 
in general make-up. This rock has been in part replaced by mag- 
netite (see plate 7, figure 4). 
ad The tabular dikelike rock running from the horse, through the 
ore into the hanging wall, is Pochuck pegmatite of dioritic com- 
position, co-related in origin to the magnetite and slightly over- 
lapping it. In places, such as this, it cuts the magnetite, but again 
may be cut by the magnetite itself; the magnetite may also in other 
instances occur interstitially in end-stage relations. 
This thin, tabular, dikelike mass remains constant in position and 
general relations, and varies but little in thickness, as the ore is 
followed down the pitch. It does not seem possible that such a 
structure could exist in the form and position it has if the ore body 
had ever been folded. 
e The late Precambrian basic dikes, first described by J. F. 
Kemp,’ cutting the ore body. These are essentially camptonites, 
and since they are found in many places in the Highlands, cutting 
all the various units, they are without much question regarded as 
late Precambrian in age. Any later compressive stresses productive 
of folding should be recorded on such erect, thin, tabular bodies, 
especially since many of them stand almost broadside to the direc- 
tions of thrust in Taconic and Appalachian times ; they show no trace 
whatever of Appalachian movement and accompanying folding, 
although they are sometimes crushed and faulted by the block 
faulting of Triassic times. 
It follows from the foregoing that most of the folded structures of 
the Highlands may indeed be, and probably are, inherited from the 
highly metamorphosed, previously folded Grenville strata, as 
postulated by the writer, and that the orogenic processes of Taconic 
and Appalachian times were productive only of crush-zones and 
thrust faults in these rocks. 
f Rock included in the ore. Blocks of rock included in and 
146 Kemp, J. F. Amer. Jour. Sci. (3) (35) p. 331. 1888. It should be 
noted that Ries and Bowen regard similar dikes at Franklin Furnace as 
Post-ordovician. Econ. Geol., v. 17, 1922. 
