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Chutes and its tributaries, to the depth of more than a thou- 
sand feet, without exposing the basis on which they rest. 
They are usually quite horizontal, from a few lines to twenty 
feet in thickness, and very accurately stratified. 
Psuc-see-que creek, one of the tributaries of the Des 
Chutes River, flows through a valley of a remarkable char- 
acter, as its sides consist of several alternate strata of Diato- 
maceous material and Columnar Trap or Concrete. Near the 
base of this series of layers is a stratum, three feet in thick- 
ness, of brilliant white Feldspathic Pumice, so soft as to be 
easily crumbled in the fingers. Above, and lying upon this, 
is a line of dark carbonaceous matter, less than a quarter of 
an inch in thickness, from which up into another layer of 
pumice projects the remains of the branches of some small 
plant, which had apparently been killed by the overflow of 
the Pumice. Lieut. Williamson gives a striking view of 
this locality, and speaks of it in the following terms: “ This 
river cafion is very remarkable. Its sides vary from 800 to 
2000 feet in height. The river has cut down its bed to this 
immense depth, through successive strata of Basalt, with 
occasionally a deposit of Infusorial marl and volcanic Tufa, 
which has sometimes hardened into a kind of Conglomerate 
Sandstone, ten or twenty feet in thickness, and of a white, 
grey, or reddish color. We followed down this cafion for 
about five miles, when a rocky spur cut off all further pro- 
gress, and compelled us to attempt the ascent. This, with 
great difficulty, we accomplished, and found ourselves on a 
plain, thinly dotted with sage bushes and clumps of grass. 
We continued our course, and, after crossing the bed of a 
torrent of the rainy season, came to a very small stream 
called Psuc-see-que by the Indians. It was sunk ina ecafion 
about 500 feet deep, cut through successive strata of Basalt, 
Infusorial marl, Tufas, and Conglomerate Sandstone, like that 
found in the Mpto-ly-as cafion.” (pp. 84, 85.) 
Another locality at which these remarkable deposits occur, 
is on the Pit River, and Lieut. Williamson’s description gives 
such a good idea of the mode of their occurrence that I 
transcribe it, also, below. 
