Grove Karl Gilbert (1843–1918) began his work in professional geology in 1869 as “local assistant” on the newly established Second Geological Survey of Ohio (the “Newberry Survey”). He worked without salary but received $50 per month for expenses. Gilbert investigated Williams, Fulton, and Lucas Counties, the three most northwestern counties adjacent to the Michigan State line. The area extended from Indiana on the west to Toledo at the western end of Lake Erie. His originality, analytical power, and clear verbal and graphic exposition, which were the distinguishing characteristics of his work throughout his career, are completely exhibited in this his earliest work, published in nine articles and reports from 1871 to 1874.

Gilbert’s maps of glacial geology of Williams and Fulton Counties are noteworthy for their detail and accuracy. He was the first to discover and map the major end moraines of the Maumee basin, from east to west (youngest to oldest): the Defiance, Fort Wayne, and Wabash Moraines. Gilbert found that the drift sheets of the moraines were actually multiple and that the uppermost drift was draped over a core of older material, a concept not to be widely recognized until almost 50 years later! Gilbert discovered the continuity and mapped the beach ridges now called, from highest to lowest, Maumee, Whittlesey, and Warren.

After distinguished work in the West from 1871 to 1881, Gilbert returned to the East and, among other projects, began to study the glacial geology of New York, especially Niagara Falls and the Lake Ontario raised beaches. In his classic study of the origin and retreat of Niagara Falls, he concluded that the Horseshoe Falls had retreated at the rate of 5 ± 1 ft/yr.

Gilbert’s other work in the Ontario basin was on the uplifted shorelines of Lake Ontario, the character and amount of their later tilting, and the surface features and drainage channels of the Rochester region. He was impressed by the boulder pavements in the till and by the evidence of glacial and postglacial folding and faulting, on which he published several papers.