522 THE JOURNAL OF GEOLOGY. 
practically nothing could be inferred regarding the relations to 
one another of the fossil-bearing horizons in the different locali- 
ties. Many of the fossils imperfectly preserved, as most of them 
were, appeared to be undoubted Silurian forms, while others 
possessed a very decided Cambrian aspect, but in no case were 
the faunas extensive enough to warrant an exact arrangement of 
the succession. All the fossils that have been mentioned or 
recorded from the lmestones of Missouri have recently been 
tabulated by Winslow & Robertson.’ By these tables and the 
accompanying paragraphs of explanation the utterly intrustworthy 
character of the faunal evidence thus far obtained for separating 
the Ozark series of Missouri into its proper terranes is admirably 
shown. Of the total of 151 entries more than one-half of the forms 
are duplicated; only twenty-two are specifically different and of 
this number but half a dozen are referred to species occurring in 
other localities. Although considerable information concerning 
the geology of the district has been obtained there yet remains 
to be done much detailed work. What is true in regard to the 
fossils in the strata of this region is equally applicable to those 
found in other portions of the uplift, except that in most other 
localities they are of even rarer occurrence. 
The Silurian rocks of well determined age which lie above the 
lower part of Ozark series of Magnesian limestones occur chiefly 
in the eastern part of the region. They are best exposed along 
the Mississippi river between St. Louis and the mouth of the Ohio, 
and include the Trenton limestone, the Hudson shales and certain 
Upper Silurian limestones. Farther south in northern Arkansas 
strata thought by Williams? to represent a part of this sequence 
are reported. But it is beneath the Trenton in the eastern por- 
tion of the uplift that the difficulty comes in attempting to fix 
the geological age of the strata. 
As explicitly stated elsewhere? the Ozark series of Broadhead 
includes both Silurian and Cambrian, instead of the latter alone, 
t Missouri Geol. Sur., Vol. VI, pp. 380-385. Jefferson City, 1895. 
? Arkansas Geol. Sur., Ann. Rep. 1890, p. 108. Little Rock, 1893. 
3 KEYES: Missouri Geol. Sur., Vol. IV. Jefferson City, 1894. 
