Reriev} of Recent (Teologlcal Literature. 325 
rocks dip under the saccharoidal sandstone, and the Izard and St. Clair 
limestones which represent the upper members of the Lower Silurian 
system in the Batesville manganese region, to the south of the iron 
region. 
The ores in the northwestern part of the state are probably on the 
same geological horizon, or perhaps somewhat in the Boone chert of the 
Lower Cai-boniferous. 
The ores of the Arkansas valley are in the Carboniferous and Lower 
Carboniferous. 
The iron ores of the Ouchita mountains occur in a series of novac- 
iilytes, siliceous shales, quartzytes and sandstones, though most of the 
deposits are immediately associated with the novaculyte and the siliceous 
shales. These strata are regarded Lower Silurian. They have furnished 
a few graptolites which Dr. Gurley regards as of Trenton age, but "the 
exact stratigraphic relations of some of the graptolite shales to the 
novaculytes are as yet uncertain." This is the same novaculyte series 
that contains the manganese deposits, and has a thickness, sometimes, 
of 450 feet, in other places thinning out altogether. The ore, the erup- 
tive associations, the novaculyte, the slates, the titanium in the Magnet 
cove magnetite, the non-fossiliferous nature of the strata and the man- 
ner of occurrence of these deposits furnish many parallels with the ores 
of the Mesabi iron range in Minnesota, and strongly suggest a proba- 
bility of equivalence of age. 
The iron ores of southern Arkansas are in the Eocene of the Tertiary, 
and mostly below the Claiborne horizon of that series. These are lim- 
onites and small quantities of carbonates. Of these the author enters 
into a careful consideration of their origin. lie traces them tlirough 
the following stages. 
(1) The derivation of the iron from the decay of the rocks in the 
drainage area of the sea which in Tertiary times occupied the position 
of the present gulf of Mexico. 
(2) The solution and transportation of the iron in the form of soluble 
organic and inorganic salts. 
(3) The precipitation of the iron as oxide or carbonate in lagoons or 
bogs along the coast. 
(4) The segregation, as carbonate (clay ironstone) of the iron in-ecipi- 
tated in the above forms. 
(5) The conversion of the carbonate into the hydrous sesquioxide of 
iron (limonite) after the lagoons on the coast of the Tertiar}' sea had 
been elevated into a land area. 
Although the iron ores of the state are at present commercially value- 
less, this is a valuable report. It sets at rest the ardent expectations of 
some prospectors and deprives them of their wealth, so far as it could 
consist in imaginary stores of iron ore, but it will be found to conduce 
greatly to the wealth of the people at large. It will forestall future ill- 
ilirected expensive exploration throughout the regions described, and 
will allow the citizen to prosecute in quiet tlie peaceful pursuit of such 
industries as the state actually possesses. 
