Rosendale cement is a natural hydraulic cement that was produced in and around Rosendale, New York, beginning in 1825.[1] From 1818 to 1970 natural cements were produced in over 70 locations in the United States and Canada. More than half of the 35 million tons of natural cement produced in the United States originated with cement rock mined in Ulster County, New York, in and around the Town of Rosendale in the Hudson River Valley.[2] The Rosendale region of southeastern New York State is widely recognized as the source of the highest quality natural cement in North America.[3] The Rosendale region was also coveted by geologists, such as W. W. Mather, a geologist working for the State of New York, for its unusual exposed bedrock.[1] Because of its reputation, Rosendale cement was used as both a trade name and as a generic term referring to any natural hydraulic cement in the US. It was used in the construction of many of the United States' most important landmarks, including the Brooklyn Bridge, the pedestal of the Statue of Liberty, Federal Hall National Memorial, and the west wing of the United States Capitol building.[4]