The name “rock stream” as a geologic term has been in use but a very short time, having been first employed by Whitman Cross and Ernest Howe in, connection with certain very remarkable accumulations of rock-debris described by them in the Silverton Polio (Colorado),2 which was published in 1905. These rock-debris masses were found only on the floors of glacial cirques at the head of the valleys and presented features strikingly different from ordinary talus slopes. To quote the above named authors:
“The most striking of these masses, and those to which attention was first directed, closely resemble debris-covered glaciers a t the heads of the basins or cirques in which they occur. The surfaces are hummocky and uneven, depressions that strangely simulate crevasses frequently occur, and concentric ridges and depressions are often seen at the end of the accumulations, which are abrupt and have steep . . .