227 
PORTLAND-CEMENT INDUSTRY IN MISSOURI. 
Prior to the year 1902 no Portland-cement plants existed in Mis- 
iri. In that year, however, the St. Louis Portland Cement Com- 
ny commenced operations, while in 1903 the Atlas Portland Cement 
mpany began shipping. Several other plants have been planned, 
t at present the two above named are the only ones in operation. 
The plant of the St. Louis Portland Cement Company is located at 
ospect Hill station, near the northern limits of the city of St. Louis, 
ic limestone used is of Mississippian age, and is quarried at Fort 
llefontaine. 
Shales of Coal Measures age are quarried near the plant and, 
aether with the loess clays which overlie them at this localit} 7 , are 
ed for mixing with the limestone. 
The plant of the Atlas Portland Cement Company is located at 
isco, Pike County, a few miles south of Hannibal. The materials 
ed are a Mississippian limestone, from a quarry adjoining the mill, 
d a shale quarried near Severton. This shale is probably of Ordo- 
jian age, the Hannibal (Mississippian) shales near the plant being 
parently unfit for use. Selected specimens^of the limestone used 
dyze as follows: 
Analyses of Mississippian limestone, llasco, Mo. 
ica (Si0 2 ) 0. 40 
imina ( ALO, ) 1 
V l 6 ) .44 
n oxide (Fe 2 3 ) i 
ne carbonate (CaC0 3 ) 97. 99 
■gnesium carbonate ( MgC0 3 ) .42 
0.54 
.42 
97.74 
.40 
CEMENT RESOURCES OF MONTANA. 
By W. II. Weed. 
Limestone is confined practically to the western, mountainous part 
the State, where it is found in great abundance along the flanks of 
3 mountain ranges. In the Plains region, which comprises the east- 
i two-thirds of the State, only, Cretaceous rocks are found, except in 
3 local dome-shaped uplifts of the Little Rock, Judith, and Snowy 
mntains. The Cretaceous formations hold lenses and concretions of 
restone, which are locally available for burning to quicklime where 
tter material is too far distant for economic use. 
All the Paleozoic formations contain limestone beds, but the great 
aestone series is that of the Carboniferous (Mississippian), whose 
