1885.] Zhe Winooski or Wakefield Marble of Vermont. 129 
Most commonly it is a hard, dark red sandstone containing, be- 
sides a large percentage of silica, eight or nine per cent of potash, 
about the same of iron, and more or less of lime. The composi- 
tion of the rock is not uniform, but differs greatly in different por- 
tions even of the same stratum. 
The color, though chiefly dark red, is sometimes light red or 
even reddish-buff. Moreover the entire formation, which is about 
two thousand feet thick; includes limestones, dolomites, slates 
and shales, though the red sandrock is, in most places, by far the 
most conspicuous member of the formation, and forms the greater 
part of its thickness. Still, in some localities other beds make 
up a not inconsiderable portion of the whole, as the following 
section taken at Swanton by Sir William Logan, and given here 
with some modification, shows: 
Feet. 
I. White and red dolomites (Winooski marble) with sandy layers ;—some of 
the strata are mottled, rose red and white, and a few are brick red or In- 
dian red. Some of the red beds contain Conocephalites adamsi and C. 
wvulcanus 370 
. Gray argillaceous limestone, partially magnesian, holding a great abun- 
dance of oy incipiens . IIO 
« Buff, sandy dolomitëseise i sa 40 
Dark gray and eek black slate, parai magnesian, with thin bands of ~~ 
sandy dolomite. The slate contains fossils as Odollela cingulata, Orthi- 
sina festinata, Camerella antiquata, Conocephalites teucer, Paradoxides 
thompsoni, P. vermontana 130 
- Bands of bluish mottled dolomite, mixed with patches of gray pure lime- 
stone and gray dolomite and bands of gray micaceous flagstone with 
fucoids 60 
Qə 
P 
v 
A mile or so north of the above section other strata, occur as 
follows : 
6. Light gray more or less dolomitic sandstones and “ some of which are fine 
grained, others are jipes conglomerate.” These åre interstratified with 
bands of whit . 630 
7. Bluish thin bedded ion flagstones and slates, containing ‘ Cue 
cephali sus and fucoids 60 
8. Bluish and yellowish mottled dolomite 120 
9. Yellowish and yellowish-gray sandy dolomite s 600 
Still further north, on the Canada line, there are additional 
strata, though not well exposed, but in general Sir William gives 
them as follows: 
10, Buff and whitish sandy dolomite, holding a great amount of black and 
gray chert in irregular fragments of various sizes up to a foot in length 
so six imeli wide. There are also masses of white quartz. Thickness 
Lcon) 790 
VOL. XIX.—NoO, 11. 9 
