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STATE AGRICULTURAL SOCIETY. 
on the map by angular markings, and is distributed, with some 
interruption, over a curvilinear strip of country parallel with 
the Sandstone district; cropping out in bold escarpments 
along the Mississippi and Wisconsin rivers. Its two extremi¬ 
ties touch Lake St. Croix and the Menomonee. Owing to its 
greater durability than that of the Sandstone upon which it 
rests, it frequently gives origin to bold overhanging cliffs 
along the streams, and adds not a little to the picturesqueness 
of their beautiful scenery. 
Resting upon the formation just described and exposed, now 
and then, throughout almost the entire extent of the Lower 
Magnesian district, is the 
Upper Sandstone, sometimes called St. Peter’s Sandstone, 
from St. Peter’s river in Minnesota, where it occurs as a 
prominent and continuous formation. This rock consists of 
very minute, and, in size, unvarying particles of whitish, (some¬ 
times buff, reddish or even brownish) silicipus sand, with but 
little cement. It is consequently wanting in durability, and is 
utterly incapable of serving any purpose as a building stone. 
It nevertheless contains enough cement in some localities to 
enable it to withstand the action of weathering to a considera¬ 
ble extent; so that it is not very uncommon to find vertical 
exposures of it fifty or more feet in height. Indeed, in a few 
places there are found remarkable isolated natural monuments 
of it rising out of the midst of the level plain capped with the 
more enduring Trenton Limestone. Its thickness is quite 
uniform and not far from eighty feet. On the map it is indi¬ 
cated by minute dots, and shows itself in narrow lines and 
rings, chiefly within and along the border of the Lower Mag¬ 
nesian rock. 
The Trenton Limestone Group , next in the ascending order, 
embraces what are popularly known as the Buff, the Blue and 
the Galena Limestones, and with the exception of the last- 
named, which is chiefly confined to the south-west, occu¬ 
pies that portion included within the outside border of the 
Lower Mgnesian and Upper Sandstone on the west and north, 
a line connecting Green Bay, Lakes Winnebago and Horicon, 
