Geology and Mineralogy of Salisbury. 253 
For the most part it is easily distinguished ; sometimes 
however, it might be mistaken for gneiss, and oceasionally 
from its soft texture it oo be called beri ‘slate, or 
talco-micaceous rock of Eaton. But su €2 es 
are rare. It is often fissile, and easily split pr tabular and 
thomboidal masses. Veins of fetid quartz several inches in 
thickness often intersect it perpendicularly to the strata. It 
contains iron ore, (of which the ‘brown oxide, hematitic and 
beet are most common, ) feldspar, | graphite, ma 
sulp ur, ,augite, 
be. The frequent alternations of granular limestone and 
mica-slate in this town, were noticed by Prof. Silliman in 
a former number of this Journal.* In examining them the 
geologist will be convinced of any thing sooner than of 
quartz ers mica nites ve it a pasties aggregate 
ah emarks, “of being 
named, and hardly worth the trouble of doing it.’ 
In the last number of this Festeval Prof. Dewey de- 
scribes a rock of mica-slate as resembling a pile of huge 
saddletrees ; the convex side uppermost, showing the ap- 
plication of some force from beneath. There is a rock 
of the same kind in this town, but the convexity is revers- 
ed. How any of the existing theories would account for 
ach appearances I know not. The strata are often un- 
dulating or of a zigzag form, the layers being distinctly 
parallel. There are manggpch. facts which confound the 
ea inquirer. We may suppose how such appear- 
neces may have been produeat but how they were may be 
aiitther thing. The imagination can picture an internal 
fire, heaving the massy granite above the incumbent rocks, 
ora plastic world slowly obeying the laws of affinity, and 
arranging its solvent materials as attraction mieten yet 
we might be as far from the fact as ever. 
t Vol. Il. pi 21. 
In many instances the slate 
