THE ROCKY MOUNTAIN LOCU8T IN 1- 11 
of brackish or other marshes, id which, or around which, grew luxuriant 
forests, the remains of which arc now bo be seen in the numerous reins 
of lignite coal that are exposed wherever fche edges of hills have been 
worn by water, and also in fche numerous petrified trunks of trees that 
are imbedded in the soil of the bluffs. 
At various localities these imperfect coal veins have Taken fire and -.. 
baked the overlying clay as to render its color that of brick-dust. This 
has occurred either by accidental tires, or oftener by Spontaneous com- 
bustion caused by the chemical action inherent in the alkali soil of which 
the over- and under-lying strata are composed. 
Up the river from Fort Bnford this formation is gradually replaced by 
one of different character. The whitish bluffs are replaced by those of 
a darker color, and those the character of whicli is quite different En 
stead of being sharp-cut, they are more rounding and almost entirely 
destitute of vegetation, the only plants being a few small species found 
chiefly on the sea-beach or on alkali flats. The soil is very loose and 
fragile when dry. and exceedingly tenacious when wet. It is what is 
known as (/umbo. Throughout this formation from top to bottom are 
found many concretionary rocks that have for nuclei various specif- •>' 
Cephalopod mollusks, as Ammonites. Scaphifces, Baculites, &c. 
The surface of this formation affords but poor footing for the multi- 
plication of locusts. But as the mouth of the Mussel Shell River is 
approached, these characters become less permanent, and small areas of 
good grass are to be seen on the uplands and gently sloping hills that 
lie on each side of the river. Here, too, in some of the deeper and 
more shaded canons, are to be seen small clumps of pines and juniper 
trees. At this locality we can truthfully assert that sometimes ('. spretm 
breeds. The farther this way (up stream) we come, the more pines 
and grass — good grass on bench-lands. Numerous locusts of different 
species arc found here. The farther up or the closer you draw to tin- 
mountains, the more numerous become the species and individuals of 
these native locusts. No specimens of G. spretus were seen this side <>: 
the Little Rockies. True, that form known as Melanoplus devastator is 
frequently to be met with along the river bottoms among the rank \ 
ration, where its habits resemble those of G. differentialis. It seldom 
alights upon the ground, always jumping from one plant to another, as 
do various species of Acridium. 
Ai Rocky Point, or what is known as Broadwater's Landing, we laid 
over a few da\ s in order to visit the Little L\>ck\ Mountains and the 
country adjacent to them. At this locality are numerous exposun 
the Cretaceous rocks — ver\ likely that group known as the Fort Pierre. 
Throughout the clays of which this formation Is composed are great 
quantities of gypsum and concretions, in the center oi' which latter are 
various species of shells. &c. Like the greater portion of the country 
already passed over, this vicinity also partakes of the •• bad -Iruid" char 
acter, though it contains a few small groves of pines that tend to di- 
minish the monotony. 
