20 The American Geologist. ■^"'^■' i^*^*- 
the cloak of black strata ; but no horizon of vein-bearing slates 
is known. Moreover, very many points of contact between 
the two formations have been seen by various observers, but 
I cannot find that any horizon similar' to the one at Caribou has 
been noted. The fact that there is no striking similarity in 
succession of strata between the various domes on the same 
anticline, especially where, as is true in several instances, more 
than two domes have been made on the same axis, also points 
strongly to the same conclusion reached in north and south 
traverses. The strata of this formation are markedly discon- 
tinuous in all directions ; and this is especially true of its finest 
sediments, which in other countries are normally persistent 
to a greater extent than coarse ones . 
Conditions of deposition. — The few and local conglomer- 
ates of the Goldenville have in no instance been proved to lie 
at the base of the series ; hence we cannot learn under what 
conditions its deposition began. We know, however, that 
these were so unstable as to cause the accumulation of fine and 
coarse material alternately through the period of action, the 
latter strongly predominating. The conglomerates indicate 
a probable shore line not far distant at some time or times. 
The sands and grits show a condition of quite shallow water 
during most of the sedimentation; but the slate horizons do 
not, on the other hand, prove an oscillation of the sea bottom . 
Such changes of level are more or less widespread, and the 
slate strata in the formation appear not to have a lateral ex- 
tent commensurate with that condition . Moreover, many slate 
partings are too tliin for their deposition to have occupied the 
whole time required under normal conditions of sedimentation, 
while such a secular change of depth was in progress. They 
are, however, readily explained by more local and transient 
causes . 
The sudden and blunt ending of strata in some cases, as at 
West Waverly; the rapid thinning of others,. as the whin over- 
Iving the Jo. Taylor belt of "leads" at Moose River mines: 
the very apparent non-persistence of individual and grouped 
strata over extensive areas, so that the beds are much more 
found in most other formations of great area and frequently no 
coarser, — all appear to me best explained in one way, not com- 
monly employed in accounting for the presence of extensive 
