Secondly, I am collaborating with Henri Grissino-Mayer (Valdosta State University), Mary Ingham (NASA), and Charlie Lieble (VSU), on a reconstruction of the erosional history of "Lyell's" Gully located near Milledgeville, GA. First described by Sir Charles Lyell in the mid 1800's, this site presents an interesting and well document record of gully development over the past 150 years. 

Slope retreat as preserved in dendrochonological records at Lyell's Gully.

In 1847, eminent British geomorphologist Sir Charles Lyell made a second trip to the United States. His itinerary carried him from the Fall Line in South Carolina to the deep south of Alabama. As he travelled through Georgia, he stopped in Baldwin County and observed the agriculture where the original oak-hickory-beech forests of the area had been cleared for production of cotton, and subsistence crops. Although extensive farming practices had been in effect for only three-to-four decades, Lyell noted that severe erosion was occuring in these soils. Lyell published a wood-cut of a large gully (Figure 1), subsequently referred to as “Lyell’s Gully”, that had formed in less than 20 years (Lyell, 1849). Ninety years later, H. Andrew Ireland (1939), an associate geologist with the soil conservaton service, re-exaimend Lyell’s Gully by comparing Lyell’s wood-cut print with survey data and field observations. Ireland noted substantial enlargement of the gully, and progressive erosion of cliff-faces (Figure 2; adapted from Ireland, 1939).
Despite the historical significance of this site, and the follow-up study by Ireland (1939), no one has investigated recent changes (1939-1995) at Lyell’s Gully. 

The purpose of this research, therefore, is to use modern surveying techniques, tree-ring dating, and geomorphological observations to define recent change, as well as to re-evaluate nearly two centuries of erosion that has occurred at this site. This  study will chronicle the geomorphic history of the gully by:  (1) conducting topographic surveys of Lyell Gully using a digital theodolite and a Trimble global positioning system (GPS); (2) measure the thickness of the sediment that is now present on the gully-floor (this will help to develop a sediment budget for the gully and assess rates of geomorphic change); (3) Determining the age of geomorphic surfaces using dendrochronological dating techniques; and (4) drawing inferences as to the magnitude and rates of geomorphic change at Lyell Gully since the site was first described by Lyell in the mid-1800’s. 

Reference: Ongoing collaborative research with Henri Grissino-Mayer (VSU), Mary Ingham (Nasa), and Charlie Lieble (VSU).