COLORADO IRRIGATION WATERS AND THEIR CHANGES. 67 
§ 126. The potassic and sodic oxids in these two sediments 
are nearly the same; the silicic acid, iron and alnminic oxids are 
as nearly so as we could expect to find in samples taken on differ¬ 
ent days;- with like conditions prevailing in the river, instead of 
samples taken under very unlike conditions. In this case, these 
samples show that there is very little difference in the suspended 
matter brought from the mountains by the flood water, produced 
by the melting snow, and that carried into the river by torrential 
rains within the foothills. This remark applies to the inorganic 
constituents only, and would not be strictly applicable to heavy 
rains falling within the sections where the red clays of the jura- 
triassic abound. The ignited suspended matter of May 22, shows 
an abundance of red clay. 
§ 127. The Queen Reservoir was filled with flood water from 
the Arkansas river. As the reservoirs, of which this is only one, 
are filled in this manner for the most part, I obtained through the 
kindness of Mr. W. M. Wiley a sample of the silt deposited in 
this reservoir. This matter had evidently been some time in ac¬ 
cumulating. It is difficult to see how this may have been silt 
carried by the flood waters of the Arkansas, and yet the judgment 
of Mr. Wiley and his assistants ought to be thoroughly reliable 
in this matter. When passed through a fifty mesh sieve 15 per 
cent of it remained upon the sieve. Before ignition, bits of coal 
were easily recognizable among the large fragments of roots, stems, 
etc. It is possible that these bits of coal had been swept along 
by the flood waters from Canon City or Pneblo. After ignition 
the mineral and rock particles recognizable were mica, quartz, 
felspar and grains of a vesicular igneous rock, probably andesite. 
The latter was abundant. There were also fragments of shells and 
pear-shaped bodies, being quite sharp at one end. Some of these 
were spirally marked, others apparently not. These bodies dis¬ 
solved in hydrochloric acid with effervescence, and were probably 
seed or spore cases of chara. 
§ 128. I am not familiar enough with the country to sug¬ 
gest any source for the particles of igneous rock, but if I have made 
no mistake they have probably been transported a long way. The 
part that passed through the sieve was separated into a coarser 
and finer portion by washing. The particles of the coarser part of 
this portion were largely quartz, some felspar and mica grains and 
also some of the eruptive rock. Such was the mechanical com¬ 
position of this silt. The chemical analysis gave the following 
results: 
