118 BULLETIN OF THE 
arrangement parallel to the adjacent surface of the sandstone. The 
glassy base with its accompanying dots of ferrite is best shown in sections 
from the narrow leaders running into the overlying sandstone (Fig. 12). 
These leaders penetrate the sandstone for a distance of several feet ; 
the largest, which is three inches wide at its beginning and.over twenty 
feet long, is seen under the microscope to be nearly pure glass, in which 
minute double refracting areas are abundant; the smallest leaders are 
mere threads, and in composition are essentially glass. 
Although as a whole the western trap is little changed, marked al- 
teration and hydration are shown in the upper surface of the trap of 
Gaylord’s Mountain, and in the leaders ; and it is to be noticed in con- 
nection with the much greater hydration of the Saltonstall range, that 
this zone of glassy trap corresponds to the general glassy base of the 
extrusive sheets. By the association of the intrusive trap at Roaring 
Brook with the coarse sandstone immediately above, it has probably been 
brought into contact with water to a greater or less extent, and part of 
its alteration may be attributable to this canse. No amygdules occur 
in the trap, except rarely one of a pseud-amygdaloidal character; there 
is no tendency towards a mixture of the two rocks along the line of 
junction, either of the kind seen above the extrusions or like the brec- 
cias known with certain intrusions. . 
The microscope affords no evidence that the conglomeratic sandstone 
has been indurated by heat. The sandstone is much decomposed, owing 
to alteration of its feldspathic constituents, and its grains are somewhat 
incoherent. This failure to show induration does not, however, militate 
against the intrusive origin of the trap. Similar sandstone at the base 
of Saltonstall Mountain exhibits no greater evidence of héat induration, 
although it was surely subjected to a high temperature. 
As far as both microscopical and field evidence go, there can be no 
doubt that in the case of Gaylord’s Mountain we have a well marked 
example of an intrusive sheet. No observers have given it a different 
interpretation. 
The Ash-bed in the Lamentation Anterior. Locality 8 (Fig. 5). — Two 
miles north of Meriden, near the road leading to New Britain, the fol- 
lowing section is exposed in the ridge anterior to Lamentation Mountain. 
The base of the bluff on the upper slope of the ridge shows a small out- 
crop of fine-grained, brownish red sandstone ; immediately above this 
there are twenty or more feet of tufa-like material, containing oval and 
discoidal areas of close-grained trap that we have interpreted as volcanic 
