128 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [bull. 165. 
found on the Aroostook River in Sheridan Township. The strike of 
the beds is N. 60° E. , with dips which indicate an anticline. With the 
exception of one dense indurated specimen, all these rocks show, in the 
field, their rapid deposition and their origin from igneous fragments, 
and here, as in Perham and Sheridan, the most characteristic field mark 
is the presence of little fragments of slates which might be mistaken 
for plant remains. 
VOLCANIC CONGLOMERATES OP PERHAM TOWNSHIP. 
Outcrops occur in the valley of Salmon Brook, where it is crossed 
by the wagon road running east-west through Perham Township, about 
one mile south of the north township line. The section here presented 
begins at the schoolhouse on the east bank of the stream, with thin 
slates whose cleavage planes run N. 40° E. , which are succeeded by 
fine, gray sandstones with slate and other fragments, striking N. 20° E. , 
dip E. < 75°. The sandstone on the west bank of the stream is very 
light gray, fine to medium grained, and is not distinguishable in the 
field from the volcanic sandstones in New Sweden and Sheridan, and, 
like them, contains few fossils. 
There is every indication that the three sections of volcanic con- 
glomerate described are sections across the strike of a narrow belt of 
sandstones and conglomerates extending from near Ashland Village to 
the north line of Perham Township. 
VOLCANIC CONGLOMERATES OF MADAWASKA LAKE. 
These are found typically exposed on the east shore of Madawaska 
Lake near the wagon road. Along the shore and in the lake bed the 
rock is seen broken into massive blocks by intersecting cleavages. On 
the west the sandstone is bounded by reddish slates. The general rock 
structure and field relations closely resemble the Perham conglomerates, 
and are classed as part of tne same general belt. 
PETROGRAPHY. 
VOLCANIC CONGLOMERATE ON WELTS BROOK. 
The finer varieties of volcanic conglomerates found at this point 
appear in the hand specimen as medium-grained sandstones, gray in 
color and much hardened. Most of the grains are not determinable 
by the unaided eye, but a few quartzes and feldspars attain the size of 
buckshot, and in the coarser varieties fragments of quartzose rock and 
of black, green, and reddish, extremely dense slates, one-half inch to 1 
inch in their longest diameters, with subvitreous luster, are abundantly 
found. They are so firmly embedded that they break with the rock. 
Weathering proceeds very slowly and very unevenly, so that parts of 
the rock are decayed to great depth, while other parts equally exposed 
