10 HYDROGRAPHIC REPORT 
delay, depending in a great measure upon the address shown in the employment of the dif- 
ferent modes of extrication resorted to. The snags are numerous, but being flexible or brittle 
are seldom dangerous. 
Experience alone can impart the knowledge required to enable one to navigate successfully. 
Memory assists but little in selecting the channel, for it has been known to change from one 
bank to the other ina single night. Generally, along a steep bank and a concave bend the 
deepest water is to be found, but the rule is not invariable. The water being turbid and per- 
fectly opaque, it is impossible to determine the depth as in the case of a clear stream. From 
the formation and relative positions of the islands and banks, from the eddies, the direction 
of the currents, from the pieces of drift-wood and other floating substances, the experienced 
navigator can generally determine the proper course to be selected. 
During the months of May and June, while the Colorado is rising, and before new bars have 
had time to form, the navigation is most easy. At the worst stages of the river the round 
trip from Fort Yuma to the Gulf, allowing a day or two for taking in the cargo, can be accom- 
plished in two weeks. During high water it is frequently made in three days. 
FORT YUMA TO MOUTH OF BILL WILLIAMS’S FORK. 
This section of the river is one hundred and ninety,miles in extent. The Yuma flats reach 
from the fort to the first chain of hills that crosses the river. At very low water the naviga- 
tion at this place will doubtless always be found difficult and tedious. There is nothing to 
confine the channel, and the water is spread over a wide surface filled with bars and snags. 
The bed is quicksand, and does not afford good holding ground for an anchor. There are no 
trees to which lines can be attached, and the snags are not strong enough to render much 
assistance. The least depth of water encountered was twenty-two inches. 
A low range is now entered, and for forty-four miles—from Explorer’s Pass, at the entrance 
of the Purple Hills, to Hazard Pass, at the foot of the Great Colorado valley—the river flows 
generally between hills and rocky bluffs. The average depth of the channel is less than below Fort 
Yuma, being not more than eight or ten feet. The velocity of the current is about the same. 
The bed of the stream is still composed of sand, but for the first time rocks are encountered. 
The banks are more permanent, as might be expected, than in the flat country below, and the 
position of the channel more fixed. The bed of the river, however, being composed of the 
same shifting material, bars are met with that present the same difficulties that characterized 
the previous navigation. They are not so numerous as in the open country. The more pre- 
cipitous the banks the deeper, as a general rule, is the channel. In the Purple Hill Pass and 
through the Cane-brake cafion the navigation is pretty good, though at the lower end of the 
latter pass there are one or two bars with but twenty inches of water, and at the upper end 
a cluster of rocks néar the left bank that project slightly above the surface. Ata higher stage 
they would be dangerous were their position not known. A mile above the first rapid occurs. 
The river, at its foot, impinges against the face of a vertical wall and then bends sharply to 
the left. Some caution should be exercised in making the turn. The channel over the rapid 
is good, a d the current not swift enough to occasion trouble. 
A short distance above are the Barrier islands. Several high rocks, arranged in a circle, 
OCCUPY, the middle of the stream, leaving a narrow channel on either side. That near the left 
bank is the more favorable, but the current is swift, and two or three isolated rocks just above 
add to the difficulty of the passage. A single rock, two and a half feet below low water mark, 
pocpet a wane ‘ - head of the narrowest place. Below Red Rock Gate is a difficult 
bar and then a stretch of good river. The velocity of th rent i i ion i t 
_ three and a half miles an hour. i Pore cemenn ine. portion -is-ebow 
At Three Points Bend two sharp rocks project from one bank, and a third juts out midway 
ae eg the other side. The channel glances by all three, and the passage requires care. Im- 
