143 
Derby’s Survey 
be neither prudent, or in fact possible, to ascend the river much 
higher, and we accordingly commenced making preparations for a 
boating expedition.” ^ 
The ebb tide ran at the rate of five and a half miles an hour, 
and the next day they saw, as it was running out, the ”bore,” 
or tidal wave, booming in to meet and overwhelm it. 
“A bank of water some four feet in height, extending clear across 
the river, was seen approaching us with equal velocity; this huge 
comber wave came steadily onward, occasionally breaking as it 
rushed over shoals of Gull and Pelican islands; passing the vessel, 
which it swung around on its course, it continued up the river. The 
phenomenon was of daily occurrence until about the time of neap 
tides.” 
At Howard’s Point the vessel was anchored while the party 
continued the exploration in the small boat. The Cocopas 
whom they met were entirely friendly. These people wore no 
clothing beyond the breechcioth, and were plastered from head 
to foot with mud. The width of the river varied from two 
hundred yards to half a mile. At one place they passed a 
Cocopa village, near which lay an old scow made from waggon- 
boxes which had floated down |from the ferry at Yuma. On 
the 13th they met Major Heintzelman coming down-stream, 
and as he had taken field notes Derby considered it unneces¬ 
sary for him to proceed, and they went back in company to the 
ship, arriving there the same afternoon. The vessel was then 
worked three miles farther up, where her cargo was discharged 
to be taken by teams to the fort. Heintzelman was accom¬ 
panied by a Dr. Ogden and a Mr. Henchelwood, “proprietors 
of the ferry.” The Craig gang had been destroyed earlier this 
year, and these men had probably established a new ferry. 
While lying at this berth, the vessel was roughly tumbled 
about by the tidal wave, till she broke from her anchor and 
drifted rapidly up-stream. This was the highest and most 
powerful spring tide, and the situation was full of peril. The 
' Reconnaissance of the Gulf of California and the Colorado River made in 
by Lieut. G. H. Derby. Ex. Doc. 81, 32nd Congress, ist Session, Senate, 
