246 Notice of a singular Conglomerate, &c. 
probably between 10° and 15°—I say probably ; for I had 
no clinometer with me. The tuff, near the junction, has 
a partial and imperfect stratification ; but farther from this 
line, the marks of stratification entirely disappear. In gen- 
eral, the rock is composed of rounded masses of greenstone 
(basalt ?) and sandstone, united by decomposed and com- 
minuted greenstone and wacke. Near its junction with 
the sandstone, I found a few pebbles of quartz and feldspar: 
but these are rare. The imbedded masses vary from the 
size of a pea, to one and even two feet in diameter. Most 
of these massessare compact, some are vesicular, and a 
ew, perhaps, are amygdaloidal. The base too is sometimes 
vesicular, like the slag of a furnace. Near the line of 
junction, I observed in some instances, what Dr. MacCul- 
loch calls “‘ a troubled mixture’’ of the two rocks, and nu- 
merous alternations a few inches in thickness. The bed 
appears to be very irregular in its width—or perhaps in 
some cases the tuff alternates with the greenstone. In 
some places I noticed the width of the tuff to be between 
a quarter and an half ofamile ; and on the side next the 
greenstone, the imbedded nodules appeared to be less 
numerous. | did not however find the actual junction of 
the tuff and the greenstone :—but perhaps some future ob- 
server may be more fortunate. 
The sandstone imbedded in the tuffis the same as that 
which lies above it. his fact, unconnected with others, 
come to the trap tuff, and going a little farther, you meet 
e om yi th “hus it appears 
that the greenstone contains at least one bed of the red 
