In order to better understand changing land use in the downtown Austin area as well as investigate patterns of change in the Colorado River terrace structure, a geomorphologist placed deep trenches in the Colorado River terraces.

An innovative trenching and sampling system was devised which would ensure the safety of the geomorphologist while he inspected terrace profiles in up to 30-foot-deep trenches. By welding massive iron I-beams together, a strong, ladder-like shoring framework was constructed on which the geomorphologist could climb down into deep shafts and document the various strata.

Although no evidence of prehistoric occupation was noted, extensive data were collected to augment the body of knowledge on terrace development along the lower Colorado River.

Subsequent excavations for the basement parking garage of the new City Hall building unearthed a fragment of a mastodon or mammoth bone. These giant elephant-like animals died out at the end of the last ice age, approximately 12,000 years ago. The disarticulated bone fragment fell out of a deep gravel deposit representing an ancient channel of the Colorado River. Work on the City Hall basement was temporarily stopped while archeologists combed the area where the bone was found. However, no other bone fragments were located. Archeologists surmised that at some point in prehistory a proboscidian died and fell into the Colorado River. As it decomposed, its bones became disarticulated and washed downstream. This portion of the animal's radius bone found its final resting place under what would become the main governing institution of Texas' capital city.