PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 141 
abundant, and again it is almost entirely absent. Of the feldspars the 
triclinic variety is usually in excess. The chief point of note in this case 
is that the hornblende and plagioclase occur in much larger proportion 
in the inclusions than in the granite proper. There are also found in 
this rock narrow vein-like inclusions which are light gray in color, of 
fine texture, and very hard and compact. These consist of quartz and 
feldspar, with only rarely a shred of mica and hornblende, or grain of 
magnetite. 
VInAL HAVEN.—The Vinal Haven rock is of much finer texture than 
thatof Hurricane Island, and contains a larger proportion of plagioclase. 
It contains a little hornblende, though in very sparing quantity. <Ac- 
cessories are not abundant. Small crystals of sphene are occasionally 
found, occurring in close contact with the mica lamin, but they are not 
plentiful. I have seen but few inclusions from this locality, and they 
differ from the containing granite only in their finer texture and perhaps 
increased proportions of feldspar. The vein-like inclusions noticed in 
the Hurricane Island rock occur also here, and are of the same com- 
position. 
BIDDEFORD.—I have seen but two of the nodules in these granites. 
They differ from the inclosing rock only in their finer texture, increased 
proportion of biotite, and perhaps slight diminution in the proportional 
amount of quartz. 
The results of the examination may be briefly summarized as follows: 
The nodules differ from the surrounding rock in their increased propor- 
tional amounts of biotite, or hornblende, and magnetite. In the majority 
of cases there is also an increase in the amount of feldspar, chiefly a 
triclinic variety, and a corresponding diminution in the amount of quartz. 
This, however, is not invariably the case. With the exception of the 
colorless needle-like crystals, they in no case contain minerals not found 
in the enclosing granite. These results agree closely with those of Mr. 
J. A. Phillips,* who has examined similar formations in granites of other 
localities, and who considers them as of concretionary origin; ‘‘as the 
result of an abnormal arrangement of the minerals constituting the 
granite itself.” 
FEBRUARY 1, 1883. 
*On Concretionary Patches and Fragments of other Rocks contained in Granite’ 
J. A. Phillips, esq. Quar. Jour. of Geol. Soc., vol. xxxvi, 1880, p. 19. 
