W. M. Fontaine—Primordial Strata of Virginia. 369 
strata numbered from (1) to (8) denote those thus numbered in the 
descriptions, while (c) represents the syenites against which 
these lean with a high northwestdip. This section peor the 
he 
a on the canal, but on the slopes of t untain 
ascending from the west (8) and the overlying strata are crowed 
over to some extent on the outcrop of the subjacent rocks. 
rom the occurrence of the quartzite stratum at (a), and the 
att that the Primordial strata ascend to the summit of the 
syenitic mountain, it might, at the first glance, be supposed that 
the slates at (b) are merely the extension of the strata on the 
west in a more highly altersd condition. But this idea is forbid- 
den by the great difference in the thickness of the western and 
eastern quartzites, and by the total change in the character of 
the beds, those on the east being a great mass of mica slates, 
quite revularly bedded, and showing none of the alternations 
of strata seen but a little distance away on the west. is 
relative position of the two systems of bedded ake explains 
the fact mentioned by Prof. Rogers as occurring in the more 
northerly portion of the State, where Primordial strata with 
northwest dip lie upon the edges of the slates of the ridges which 
dip to the southeast. This would occur here were the syenitic 
mass absent, and, as we shall see, it does ot me a a aap ridge 
ted north. The following section, repre 
sentation ~ ee stratification of series @) Gg pee (11). As 
far re (9) and (10) are concerned, it is in part ideal, and I do 
not insist eum the correctness of my estimate of their thickness. 
Section II. 
. No. (8) with subjacent strata. (9) Gray and reddish shales and sandstones. 
11) Upper shales and Calciferous strata. 
(oy Potsdam shales and quartzites. 
No detailed examination was made at this point of the 
Primordial rocks. At the west base of the syenitic range, 
gray Pabalcs and kaolin shales, very imperfectly exposed, were 
seen to pass a little distance up the mountain. They have a 
high southeast dip, showing the inversion of the lowest portion of 
the Primordial strata in this region. It is probable that some 
of the lower strata have been ingulfed in the overturn. f 
Rogers states that from this point to the southwest the inversion 
enerall ails. 
. ead whine [To be continued. ] 
