EARLY BEDROCK INVESTIGATIONS IN NEW HAMPSHIRE BY C. T. JACKSON AND C. H. HITCHCOCK

In 1823, Governor Levi Woodbury proposed the establishment of an agricultural survey of New Hampshire that included chemical analysis of soils. Although not adopted, Woodbury may have set the stage for Governor Isaac Hill’s success, fourteen years later, in authorizing a geologic/mineralogical survey (Hitchcock, 1874). Charles T. Jackson was subsequently appointed in 1839 for a three-year term as NH’s first state geologist.

Experienced, and well-respected following his three-year tenure as Maine’s first state geologist, Jackson and several assistants (often his pupils) surveyed mostly SE to NW transects, town to town, across the State to “examine all beds or deposits of ore, coal, clay, marls… that may be useful or valuable.” His aim was to “assay and analyze.. and map” the state’s resources (Jackson, 1844). As expected for the times, he emphasized commodities that supported agriculture, mining and commerce. Rather than creating areal map units, Jackson’s 1844 map noted individual localities of principal lithologies and specific deposits. The locations on his map do provide a basis for reconstruction of an initial geological map of the State.

In common with C.T. Jackson, Charles H. Hitchcock served as the 2^nd State Geologist of Maine (1861-62), and the 2^nd State Geologist of New Hampshire (1868-73). With the advantage of early geologic training from his prominent geologist father and mentor, Edward Hitchcock, C.H. Hitchcock greatly extended Jackson’s efforts in the field and in interpretation. Having a longer time, a larger entourage of assistants (many his Dartmouth students) and better topographic base maps, Hitchcock defined, mapped and arranged chronologically nine major rock groups, extending them between Jackson’s cross-strike transects. The result was the first truly geological map of New Hampshire. His “elephant folio” Atlas and huge wooden relief maps illustrate the geology contained in his monumental three-volume treatise. Using forty map units, the broad map pattern differs little from today’s new maps. “Before his time” in many ways, Hitchcock recognized the critical units and structures that form the basis of later understanding of nappes and fault zones. His interpretations anticipated many of the features and controversies central to our understanding of New Hampshire and New England geology.