The chief officer, Dr. Ferdinand V. Hayden, was an unusually capable geologist. In addition, he possessed an inspiring personality and statesmanlike views. There were nineteen scientists directly under his command. The personnel included James Stevenson, managing director; Henry W. Elliott and Thomas Moran, artists; Professor Cyrus Thomas, agricultural statistician and entomologist; Anton Schonborn, chief topographer; William H. Jackson, photographer; George B. Dixon, assistant photographer; J. W. Beaman, meteorologist; Professor G. N. Allen, botanist; Robert Adams, Jr., assistant botanist; Dr. A. C. Peale, mineralogist; Dr. C. S. Trunbull, physician; Campbell Carrington, in charge of zoological collections; William B. Logan, secretary; F. J. Huse; Chester M. Dawes, son of Representative Henry L. Dawes of Massachusetts; C. De V. Hegley and J. W. Duncan, assistants. Barlow’s army detail also had a competent and well-balanced personnel.[145] A military escort, including Lieutenant Doane, rounded out these expeditions and provided all that could have been desired in point of training and ability. Each detachment had a retinue of helpers. Two technical studies and scientific reports, which not only substantiated but actually enhanced the findings of the previous civilian explorations, resulted from these two expeditions. Hayden’s party left Fort Ellis, near Bozeman, on July 15, 1871. Upon reaching the junction of the Yellowstone and Gardner rivers they elected to ascend the latter. It was a good choice because within the hour they beheld a white mountain which resembled a vast cascade of frozen snow. The Mammoth Hot Springs Terraces “alone surpassed all the descriptions which had been given by former travelers.”[146] As this expedition progressed, the geological record was interpreted. Thereafter, rocks were identified as travertine, gneiss, rhyolite, dacite, basalt, breccia, geyserite, sinter, and obsidian. Trees and plants were likewise classified, and in addition to geysers, springs and pools there were fumaroles and _solfataras_. Geological speculations were formulated relative to petrified forests, Grand Canyon, the lake’s former Snake River outlet, and the relationship of heat, water, and “plumbing” essential for geyser action. [Illustration: _The Hayden expedition in camp_]