eature of the state has long been known
in the Ozark uplift, a broad plateau with gentle quaquaversal slopes
rising to a height of more than one thousand five hundred feet above
mean tide, and extending almost entirely across the southern part of the
district. On all sides the borders of this highland area are deeply
grooved by numberless streams flowing in narrow gorges. Against its
nucleus of very ancient granites and porphyries the Ozark series of
magnesian limestone was laid down. Then the area occupied by these rocks
was elevated, and around its margins were deposited successively the
other members of the Paleozoic. The Ozark region was thus the first land
to appear within the borders of the present state of Missouri." He
further says: "Although it has long been known that the Magnesian
Limestones are older than the Trenton, and that they lie immediately
upon and against the Archaean crystallines unconformably, their exact
geological age has always remained unsettled. There seems to be but
little doubt, however, that part of the series is equivalent to the
Calciferous of other regions. It is also pretty well determined that
certain of the lower beds, all below the 'Saccharoidal' Sandstone
perhaps, are representatives of the Upper Cambrian or Potsdam. These
conclusions appear well grounded both upon stratigraphical and faunal
evidence. The rocks of the Ozark region have not as yet received the
necessary detailed study to enable the several lines of demarkation to
be drawn with certainty. This investigation is now being carried on as
rapidly as possible, and promises very satisfactory and interesting
results in the near future."

"The early geological reports represent the Magnesian Limestone series
as made up of seven members. Following Swallow, these may be briefly
described in the present connection. Beginning at the top, they are:

First Magnesian Limestone.
First, or Saccharoidal Sandstone.
Second Magnesian Limestone.
Second Sandstone.
Third Magnesian Limestone.
Third Sandstone.
Fourth Limestone."

"The Fourth" Magnesian Limestone, or lowest number of the Ozark series
recognized, has its typical exposures along the Niangua and Osage rivers
in Morgan and Camden counties.

Professor Swallow, in his Missouri Geological Survey Reports I. and II.,
1853 and 1854, says: "Caves, natural bridges and subterranean streams
occur in the valley of the Osage and its tributaries." The same
authority of forty years ago a