Kaieteur Falls which is one of the longest and widest rivers in South America and the longest river in Guyana. The falls were discovered by Europeans in 1870 by a party led by Charles Barrington Brown, a British geologist appointed as a government surveyor to the colony of British Guiana. Brown and his partner James Sawkins had arrived in Georgetown in 1867, and while they did some of their mapping and preparation of geological reports together, some work was performed in separate expeditions, and Sawkins was taking a break from his work at the time of Brown's discovery of Kaieteur. At this
American Falls Dam the present American Falls Dam formed a reservoir in which more than of sediments (clay, silt, and sand) were deposited. This series of basalt flows and original sediments were covered by the new lake bed sediments and are named the Snake River Group and the American Falls Lake Beds. These events occurred up until the late Pleistocene, less than one million years ago. The Snake River has continued to erode its channel in the basalt and modify the lake bed sediments until the present time. The dam at American Falls is on the Snake River Plain at an elevation of