Mcgiiiiuj Scries of Xova Scotia. — Woodman. 21 
series of strata. Tliis is l)y tho deposition of the sediments 
of the (loldenville in nuHleralely shallow water, upon a floor 
essentially llat under the area now covered by the strata, and 
influenced by somewhat violent currents and waves, constantly 
shifting- their relaiions. Tidal changes in depth of water and 
direction of transportation may sufifice to account for some of 
the phenomena ot distribution of sediments, but not for all. 
These currents created unevennesses of bottom through dif- 
ferential deposition, and changed the character of the detritus 
in any place suddenly, according to the direction and force of 
the flow at the time. 
The known thickness of the formation is more than 17,000 
feet. How much lies below the exposed part we cannot tell. 
It niav be considerable ; it can hardly be less than hundreds of 
feet, and probably amounts to thousands. The top is not 
essentially different from the bottom in texture. There is 
perhaps a finer average of the whin and a greater abundance 
of the slate near the center, although any difference which 
exists is not marked. Taken as a whole, the quartzytes keep 
their texture, and there is no such progression from a coarse 
base to a fine summit, or vice versa, as often is found. This 
indicates that the conditions of sedimentation were the same at 
the top as at the bottom. Rut the 17,000 feet represent solid, 
compact rock. How much bulk the sediments lose by super- 
incumbent pressure and by loss of water, both during and af- 
ter deposition, it is diflficult to estimate. It is safe to say, how- 
ever, that the strata now exposed would, in their original un- 
compacted state, have occupied a vertical column far higher 
than the present thickness of the formation. This does not 
mean that they were ever thicker to that extent ; but it does 
mean that, to keep the sea bottom at a fairly even depth, the 
sinking of the -iriginal bottom, minus the compressive com- 
pacting of the lower strata by those continually forming over 
them, must have been equal to about 17,000 feet, and possibly 
more. The theorv of the deposition of these sediments under 
the influence of currents lends itself readily to this view of the 
position of the sea bottom and the sinking of the detritus. 
Tlic Halifax formation. 
I)istrihntio)i . — The Halifax formation is distributed in 
narrow zones or Ixmds. running with the general strike of the 
