30 THE CLAYS OF AKKANSAS. 
Throughout the region it covers in Arkansas the loess may be 
readily recognized by its fineness and by its light-yellow or buff color. 
In certain localities it becomes slightly darker in color, possibly by 
reason of the presence of organic matter, or it may even be blotched 
with dark-brown and reddish colors. Close examination of these 
blotches reveals the fact that the color is due to a superficial coating 
of iron oxide on the individual grains. 
This loess is especially suited to the manufacture of superior grades 
of brick. Care is necessary in its preparation for molding, however, 
and discrimination is required in respect to the mixture of soils from 
the neighboring hills. Where the soils of the hillsides are largely 
made up of sands and gravels derived from local outcrops of the Ter- 
tiary strata, as they are in some places about Jonesboro, Harrisburg, 
Gainesville, and Wynne, they are unsuited to the manufacture of 
good brick. At other localities, notably near Marianna, at Forrest 
City, and at La Grange, the slopes of the hills, along their lower mar- 
gin, contain many small nodules of limonite, which render the 
soils less valuable for brick manufacture. If these nodules be re- 
moved by screening, the soils can be used successfully in brick manu- 
facture. But at all these localities there are abundant deposits of 
clean loess that furnish unlimited. opportunities for brickmaking. 
The bricks made from the Crowleys Ridge loess usually burn to a 
good color — cherry-red for hard, and a lighter shade of red for the soft 
burned ones. 
Near Marianna, in the SW. \ SW. \ sec. 19, T. 2 N., R. 4 E., many 
acres are covered by a peculiarly colored modification of the loess, 
which contains a higher percentage of iron oxide than the typical 
loess. It is a very fine homogeneous deposit and fills the lower por- 
tion of all the creeks, ravines, and gullies of the neighborhood. It 
will prove a superior brick clay and will burn to a rich, uniform red. 
It is well adapted to the manufacture of ornamental front and pressed 
brick. 
The hilly country north of Poinsett County differs from other parts 
of the State in the distribution of the loess and its relations to the Ter- 
tiary strata. The loess there is found only on the slopes of the hill- 
sides or on the low spurs of the ridge wherever they extend far from 
its main mass, and it is there a less prominent geologic feature than 
it is in the country south of Craighead County. In this hilly country 
its relations to the Tertiary sands and gravels are such that in most 
localities the loess deposits are more sandy and apparently less homo- 
geneous; the quality of brick that may be made from this soil, while 
excellent, will not be so fine as that made from unmodified loess. 
In Memphis, St. Louis, Des Moines, Council Bluffs, and Ottumwa, 
Iowa; Omaha, Nebraska City, and David City, Nebr.; St. Joseph, 
