From the commemorative signboard on the hiking trail:
The Round Top Hydraulic Cement Company operated at this site from 1863 to 1909, producing
2,200 barrels of hydraulic cement per week. By the 1880's it was one of Washington County's
most flourishing businesses.
In 1838, George Shafer was authorized by the canal company to build a cement mill at the foot
of Round Top Hill. Shafer rented the mill, five stone quarry tunnels and the necessary water power
to successfully produce 200,000 bushels of cement over a period of 25 years. In 1863, the mill
was purchased by partners Robert Bridges and Charles William Henderson and renamed the
"Round Top Hydraulic Cement Company". A 16-foot diameter overshot waterwheel operated 4 pairs of
grind stones, each 5 feet in diameter. There were 8 supporting cement kilns, each fired by coal
which was shipped by canal boat. The mill employed up to 100 workers who packed the cement in
300-pound barrels, and 50 and 100 pound sacks. It was then shipped by canal boat or sent across
the Potomac River by cable for transport on the Baltimore and Ohio Railroad.
By the end of the 19th century, the use of natural cement declined in favor of slower setting
and stronger Portland Cement. In 1909, the Round Top Hydraulic Cement Company closed.
