138 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [bull. 105. 
River in Wade Township; at Masardis, and in railroad cuts south of 
Masardis. The exposures are usually but a few feet wide and can 
seldom be traced for more than 100 feet. They form thin beds in the 
slates and limestones and remain as small ridges after the softer 
sediments have been worn away. 
In thin section under the microscope they appear as an aggregate of 
quartz grains closely united, and with them considerable calcite is 
found, both in grains and as the cementing material. A few shreds of 
white mica, iron grains, and feldspars are usually also present. 
These lime-bearing sandstones are geologically unimportant, and are 
mentioned to show their lithologic relationship. As indicated by the 
table given at the beginning of this chapter (p. 119), they are consid- 
ered as a transition between the true sandstones and those with about 
equal amounts of quartz and calcite. 
CALCIFEROUS QUARTZITIO SANDSTONE. 
Under this head are included rocks of a peculiar type which have 
been called in the field felsite, quartzite, slate, and limestone. They 
occur as beds 15 feet or more in thickness, and as thin gritty layers in 
the limestone, and have a composition, as revealed by the microscope, 
of about half calcite and half other minerals, largely quartz. 
These rocks are sparingly distributed in the eastern part of the sec- 
tion under discussion, and have not been found at all west of the Hay- 
stack Ridge. The outcrops easiest of access are at Washburn Ferry, 
on the north bank of the Aroostook River, and in the wagon road 
about 1 mile east of the Castle Hill Hotel. An outcrop in the north- 
western part of New Sweden was found interbedded with fossiliferous 
slates by which its age has been determined. 
Wherever the sandstone has been found it presents a light-gray, 
glistening surface, and looks in the hand specimens like a quartzite. 
It has an uneven fracture that is sometimes conchoidal, and it weathers 
by forming a distinctly bounded }^ellow-brown zone, immediately inside 
of which the rock presents a uniform fresh appearance. This method 
of weathering and the generally massive character of the beds are 
strikingly like many fine-grained feldspathic igneous rocks, and have 
given rise to confusion in field terms. Examination of microsections 
shows an exceedingly dense rock composed of calcite and other carbon- 
ates, quartz, feldspar, muscovite, and iron. The amount of quartz 
varies in different slides from about 50 per cent down to 15 per cent, 
but without greatly affecting the general quartzitic appearance of the 
rock. The muscovite is entirely absent in some slides and pyrite is 
occasionally present. 
Analysis. — Owing to the uncertain character of this rock, Dr. W. F. 
Hillebrand made the following analysis of the specimen from New 
