PROCEEDINGS OF UNITED’ STATES NATIONAL MUSEUM. 139 
and corners are often greatly rounded and the crystals reduced to mere 
oval grains. These rounded crystals are quite small, being only from 
1™™ to 4™™ in length. The mica, as seen in the section, is in part biotite 
of the ordinary yellowish brown color; in part a colorless variety, oc- 
curring in small slender laminz which are often arranged in fan-shaped 
forms, or again in part a green chlorite, with the characteristic fibrous 
radiated structure. A few grains of pyrite are present, together with 
some epidote and numerous grains of magnetite. The quartz granules 
are frequently pierced by small ss microlites, which could not be 
accurately determined. 
SuLLivan.—The Sullivan granite is a coarse, gray rock, containing, 
so far as observed, but few accessory minerals, a few small crystals of 
magnetite, apatite, and zircon only being visible under the microscope. 
Dark nodules are very abundant in this rock, and I have examined a 
considerable number. As a whole, these are very fine and compact, 
with outlines well defined. By the microscope they are seen to be com- 
posed of essentially the same minerals as the surrounding granite, but 
in varying proportions and in a more finely divided state. But little 
quartz is present, while the feldspar is largely triclinic, sometimes show- 
ing a well-defined zonary structure. In all biotite is very abundant, 
frequently obscuring all other ingredients. Magnetite, in the form of 
small rounded grains, is usually very plentiful, together with very many 
colorless microlites such as were noticed in the Jonesboro rock. One 
of the inclusions in this rock is of so peculiar an appearance as to merit 
special attention. In size it is about 2 inches square and 6 inches long, 
with sharp angles and corners. On three sides and the ends, although 
the line of demarkation is perfectly sharp and runs in neatly straight 
lines, still there is no perceptible separation between the inclusion and 
the enclosing granite, the contact apparently being perfect. On the 
fourth side, however, there is a distinct groove traceable with a knife- 
point for several inches, as though the imperfect tluidity of the granitic 
mass had prevented its completély enveloping it. I can conceive, how- 
ever, that this effect may have been produced by weathering, as this 
side was exposed at the time of my finding the specimen. The texture 
of this specimen is too fine to allow any determination of its composi- 
tion by the naked eye. In color it is almost perfectly black. In thin 
sections the composition is found to be quite simple, consisting of mica 
scales and magnetite granules, so abundant as at times to almost en- 
tirely obscure all other ingredients. But little quartz is to be seen, and 
the feldspar is largely a triclinic variety. 
Mount DESERT.—The rock quarried at Somesville, Mount Desert, 
is a coarse pinkish gray granite, in which much of the mica is of a 
greenish color, apparently of a chloritic or taleose nature. Magnetite, 
apatite, zircon, and sphene occur as accessories. The dark nodules in 
this rock closely resemble those in that of Jonesboro. The larger 
grains that lie imbedded in the even gray groundmass of the inclusion 
