The first of these maps is a series of four that represent one of the most important explorations of the American Southwest. That of Lt. J. C. Ives of the Topographical Engineers and is from the ‘Report Upon the Colorado River of the West’. It depicts the topography and geology of the Colorado River from the Gulf to Black Canon at Fortification Rock, the present location of Hoover Dam. The nightly campsites are recorded with extensive notes of the nature of the river especially its rapids. Only two ‘white’ settlements are illustrated at Ogden’s Landing and Frederick’s. The second map depicts the whole region further upriver and extends from just west of present day Las Vegas to Gallup, New Mexico. The Little Colorado is here named the ‘Flax River’. Along with the route of Ives that of A. W. Whipple is also shown from 1853-54. The engraving is very distinctive and is the work of Baron F. W. von Egloffstein. The technique was devised by Egloffstein and involved numerous extremely fine lines and using different stages of acid exposure these help to convey altitude. These show is a remarkable three dimensional effect. Wheat says that these are some of the best maps engraved by the remarkable Egloffstein. He devotes several pages to the expedition and reproduces both of these maps. Wheat, C.I. (TM) no. 947-8.