the mohegan quarry

More than 130 years ago, the abandoned and long forgotten Mohegan Quarry was a major industry in Yorktown and a major New York State supplier of granite for buildings. Located between Lexington Avenue (once known as Hog Lane) and Stony Street and from Route 202 north to possibly Amazon Road, the quarry operated from 1890 to 1941, and at its peak in the mid-late 1920s, employed between 200 to 300 workers, depending on the number and size of the contracts it had at any given time. 

A 1926 photo of the quarry | Source: Milestone Heritage Consulting

Today, the quarry is part of Yorktown’s 343 acre Sylvan Glen Park Preserve.

While the quarry supplied granite for several prominent buildings, including at least two known landmarked building in New York City, the quarry’s success over three decades was due to a series of contracts for the Cathedral of Saint John the Divine in the Morningside Heights section of New York City. 

The Mohegan quarry was one of five distinct quarries that made up what was sometimes referred to as “Peekskill granite.”  While there was some uniformity in the stone from the different quarries, there were also variations.

Five local quarries. | Source: Carhart Master’s Thesis, 1925
Microscopic photo of golden granite | Source: New York State Library
Microscopic photo of gray granite | Source: New York State Library

Early literature about the quarry offers several hypotheses as to the origin of the yellow color.

H. Newland, author of 1916 “The Quarry Materials of New York Granite, Gneiss, Trap and Marble,” published by the New York State Museum ascribed the color to the presence of a little limonite stain distributed along the borders and microscopic cracks of the quartz and feldspar, particularly of the quartz which appeared to carry most of the coloring matter.

In 1924, a researcher noted that there were actually two shades of the golden granite: a light buff found nearer the surface of the quarry and which changed very abruptly to a deeper shade. The lighter shade had much the same mineralogy as the darker shade but lacked the deep yellow quartz.

And in 1931, another researcher noted that when the yellow quartz grains were picked out from the granite after being crushed and boiled in acid, the color was entirely removed from them indicating that the color was only a surface effect and was not due to something dissolving in the quartz itself.

The history of the quarry