262 The American Geologist. April, i89» 
(see p. 115). His report is accompanied by a series of numbered 
sections on Piney river from Ciibool to Arlington, and on the 
Gasconade from Arlington to Gasconade. I am not familiar with 
the region south of Arlington, but I have followed the Gasconade 
from the mouth of Little Pine^^to Gasconade. 
Suppose we assume the Missouri bluffs to be a base line. From 
Washington to Jefferson the series of rocks, in sight along the 
Missouri Pacific railroad, have been referred by all former geol- 
ogists of Missouri to the age of the second Magnesian limestone. 
Thej' consist of a series of siliceous dolomites ai'gillo-magnesian 
lime-stones, concretionary chert la3'ersand some shale beds with an 
occasional lenticular bed of white sandstone, in all aggregating over 
100 feet in thickness and in some places reaching over 250 feet. 
One or two thin sandstone layers are here included but the lime- 
stones above and below are the well known beds of the second. 
Such a thin sandstone layer is seen half way up the hill at Cham- 
ois and also between Chamois and the Gasconade, likewise in the 
bluff, at Hermann and a mile east. 
The first sandstone is not often seen west of Chamois. East of 
Chamois it is seen at a few places back on the hills, and at Gas- 
conade it is the highest rock, occurring near the hilltop and prob- 
ably over 250 feet above the base of the hill. A short distance 
below the Gasconade are found ver\' large tumbled masses h'ing 
near the river. A few miles east it is found banded, pink and 
white. A mile back of Hermann it is high in the hills, but not at top. 
At the count}^ line of Gasconade and Franklin it caps the hills, and 
at this place I obtained fragments of a large species of Orthocera- 
tite. All along the railroad the second Magnesian limestone 
is the lower rock, generally rising over 200 feet in the bluffs. At 
Gray's summit the Pacific railroad cuts through the first sand- 
stone, as it also does east of Pacific. (3ur section at Pacific would 
show: 
1st — Trenton limestone. 
2d — Black River beds. 
.Id — First Magnesian limestone. 
4th — 100 feet of Saccharoirtal sandstone. 
North of this, on the Missouri bluffs the first sandstone is welf 
exposed. Crossing the Missouri river into St. Charles county,, 
it and its associated rocks both above and below are well exposed. 
At the count}' line of St. Charlesand Warren the second Magnesiaui 
