458 DESCRIPTION OF THE COUNTRY BORDERING 
cases of large Orthocera, and also in the Birdseye of New York, just below the 
Trenton, measuring ten and twelve inches in diameter. 
Two miles up the first branch of East River, above Ellis’s Mill, three miles from 
Navarino, the bluish-green and buff limestones, in rough flags, like that of Dupere, 
are exposed, with a slight dip to the east. At Sturgeon Bay, fifteen miles down 
the Bay, the buff-coloured limestone rests on the blue limestone of Cincinnati. On 
the west shore of the Bay, twenty miles from Navarino, at Oak Orchard, the same 
bluish-green layers are seen about the lake-level, dipping slightly east, containing 
Phragmoceras arcuatum (Murchison, Lower, Ludlow), Pleurotomaria lenticularis, and 
the same large Pleurotomaria as at the Grand Kau-kau-lin. The next appearance 
of rock occurred at the Falls of the Oconto River, in Township 28 north, Range 
19 east, twelve miles from the coast, at Oak Orchard, in a northwest direction. 
The foot of the rapid below the Falls, is, by a close estimate of the descent of 
the river, eighteen feet above the Lake or Bay, thence up to the foot of the bluff, 
thirty-two feet; thence it is forty-one feet to the surface of lime-rock above the 
Falls, or ninety-one feet above the Lake; giving a descent in the channel of sixty- 
one feet in half a mile, of which twenty-two feet, at the saw-mill, is perpendicular. 
The following section at the Falls of Oconto River gives the succession of the 
_beds. ‘ 
18 feet above Lake. 
e 
e, é. Channel of the river. c. Irregularly bedded and siliceous bed, with geodes and crystals, fifteen feet. 6. Light gray, compact, thick- 
bedded, close-grained sand-rock, slightly calcareous, twenty feet. a. Spotted, yellow and gray, calcareous sand-rock, in thick layers, ten feet 
visible. The total height above the Lake is seventy-three feet. 
The section is taken up stream, or about northwest, towards which there is a 
slight local dip. 
The rock here is so siliceous that there are but few pieces which slake into lime 
on being burnt. Siliceous matter is nét only an ingredient, but exists in white 
spots, grains, and imperfect crystals. The small yellow spots are iron-rust, of 
which there is a notable proportion, which turn red on being burnt. Exter- 
nally, it resembles somewhat the lead-bearing rock, weathering rough, and appa- 
rently containing magnesia. It is, however, geologically far below the upper 
magnesian or lead-bearing rock of Wisconsin. The rock exhibited no signs of veins 
or veinstone. It was reported by a person engaged at the mill, who had been in 
the lead region, that he had seen lead in this rock. The composition and structure 
must be different from that seen at the Falls to produce lead in valuable veins. We 
discovered no fossils in this rock. 
At nine miles, by reckoning along the stream, above the Falls, the lower sand- 
rock made its appearance in the west bank; its elevation above the top of the last 
section very little if anything above the upper mill-dam. It rose in a bluff from 
thence seventy-nine feet (or about one hundred and seventy feet above the Lake), 
to the general level of the country. At the base, it is a soft, whitish-gray, coarse- 
grained, crystalline sand-rock, like the St. Peter’s saccharoid sandstone, but not as 
