For over 30 years, Mohegan Golden Granite quarried in Yorktown, New York was inextricably tied to the Cathedral of St. John the Divine. Through three different quarry owners, from 1898 to the mid-1930’s, this warm buff granite was used on the Cathedral exteriors.
Mohegan Granite Geology
Granite ledges in the Sylvan Glen area of Yorktown were quarried by farmers in the 1880’s for their own use. In 1890 the Mohegan Granite company began. The granite bedrock in Sylvan Glen formed in the Devonian Age, about 370 million years ago. Molten magma flowed upward through faults in the overlying rock. Eventually, after cooling, the solid granite became gradually exposed to crustal uplift and erosion.
Granite contains three key minerals: feldspar, mica, and quartz. Thus the configuration and amount of these minerals determine the rock’s color. The Mohegan Quarry produced two shades of granite, a light gray stone with a pinkish tone well suited for carvings, as well as a golden or buff colored stone. This latter stone is known as “Mohegan” or “Golden” granite. It is prized for its warm mellow hue. The color is due to the presence of a little limonite stain. Limonite is an iron ore. This stain is distributed along the borders and microscopic cracks of the quartz and feldspar.
The Connection to the Cathedral
The Cathedral’s interest in the quarry began four years after the laying of the Cathedral’s cornerstone. In 1896 Heinz & LaFarge sought out sources of granite to be used in the construction of the Choir. They looked into the suitability of granite quarries from Maine to Minnesota. One of the firm’s partners, George L. Heins, lived in nearby Peekskill, New York. He was an avid hiker and it was on one of his hikes that he came across the quarry and the golden granite.
After a process of elimination that factored in durability, color and ease of working, the architects commissioned an analysis of the properties of both Mohegan and Maine granite. Suitable laboratory analysis concluded that the Mohegan Golden Granite would prove to be durable and satisfactory. In 1898, based on the analysis, the Cathedral’s trustees authorized the expenditure of $40,000 for the exterior of the Choir. The Cathedral would become the quarry’s largest and most sustained customer. The quarry was located just 38 miles north of the building site.
“We consider its [Mohegan’s] color very nearly the ideal color for such a building. It is not only light, but has sufficient warmth to prevent any appearance of gloominess and at the same time it is not so white as to make a glaring effect upon the eye. We consider it distinctly superior to the [Maine] stone in this respect.”
Heins & LaFarge
More Mohegan Granite Specified
Between 1911 and 1913, the Cathedral’s Synod House used Mohegan granite. As well it is on the Saint Columba, St. James and Saint Ansgarius Chapels. In many cases it appears that it is not load supporting but an exterior veneer.
In the early years, perhaps between 1898 and 1900, Evelyn P. Roberts was the President of the Mohegan Granite Company. Acting as a private citizen and not a representative of the company, he purchased adjoining land and then leased it to the Cathedral. This ensured supply of the stone for future Cathedral needs and added to the linkage between Cathedral and quarry.
Supplying Granite for the Nave
By 1917, Cram and Ferguson’s designs for the Nave were complete and construction was about to proceed. Competition was fierce from the Maine quarries. In June 1917, the Cathedral accepted the Mohegan proposal for $34,000. However, work did not proceed due to World War I. In April 0f 1920, the Cathedral Trustees voted to commence construction in the spring of 1921. This was subject to the raising of necessary funds, an estimated $500,000.
The Cathedral received bids from the Mohegan Quarry and a quarry in Maine for this phase of the nave’s construction. The Trustees made the decision to go with the Mohegan bid based on several reasons. One, of course, was the continuing use of the same stone. Another was the fact that the Mohegan bid was $110,ooo lower than the Maine bid. Additionally, they discussed the possibility of the quarry closing without new orders. The execution of the contract would greatly strengthen the quarry’s business and the availability of future stone orders.
In October 1920, the Cathedral entered into a $150,620 contract with Grenci & Ellis, the quarry’s new owner. The contract was for suppling and delivering about 17,500 cubic feet of granite. This granite was for the facing of the exterior walls of the nave up to a certain elevation and for the facing of the walls of the four bays adjacent to the Crossing.
Grenci & Ellis, Inc
The first commercial quarry dating to 1890 was the Mohegan Granite Company. Evelyn Pierrepont Roberts headed up this company. After successful dam contracts, the quarry sat idle for several years. In 1896-97 a reorganization occurred with new capital and E. P. Roberts as a director. The new company formed became the Mohegan Granite Quarrying Company. Later, sometime between 1919 and 1920 Bruno M. Grenci and Thomas H. Ellis acquired the company. Ellis was the long-time superintendent at the quarry under its previous owner.
Bruno Grenci immigrated to the United States 1n 1898 at age 15. In Italy, his family worked with stone. Once in America, Grenci worked in Maine, Vermont, Pennsylvania and New York. In 1900 he went to work in the Mohegan Quarry. He left and started his own business in 1904 and in 1917, in partnership with Thomas Ellis, he associated in the operation of the Mohegan Quarry. According to records, he inspected every piece of stone before it left the property.
More Than a Quarry
The new company’s major breakthrough came in 1925. The Cathedral awarded Grenci & Ellis a series of contracts for the Nave. These contracts amounted to $5 million. Once again, competition for these contracts between the Mohegan and Maine quarries was intense. With contracts for $5 million in hand, the new company undertook a modernization and expansion that enabled it to supply Mohegan granite for the Cathedral and finished granite from other quarries for other jobs. The greatest modernization took place in the granite sheds where increased fabrication abilities took place.
Quarry Methods
Grenci & Ellis upgraded quarrying methods as well. Over the quarry’s five decades of operation, steam drilling replaced hand drilling. Compressed air drilling in turn replaced steam in the mid 1920’s. The new drilling and splitting methods led to a one third increase in the amount of marketable stone they were able to produce.
At Mohegan, granite was difficult to split on flat, perpendicular planes, wasting the limited supply of golden granite. Deep hole splitting controlled the splitting, resulting in flatter planes, less waste and more usable stone
Another method used by the quarry was broach channeling. This efficient mechanical method for extracting large blocks involved drilling rows of closely-spaced holes with a compressed air drill. Then a wide broaching bit acts to remove the webs between the holes. A few strategically placed blasting powder charges freed the block from the quarry wall. Broach channeling was faster and lower in cost than other splitting methods. It helped the Mohegan Quarry conserve the most desirable stone.
In 1930, Grenci & Ellis bought the Mount Waldo quarry in Frankfort, Maine. The acquisition enabled the company to offer a wider variety of granite. Most of the Maine granite was shipped to Mohegan for finishing. This in turn allowed it to expand its market and secure additional contracts. The last known contract with the Cathedral was for stage 4 of the exterior of the West Front.
The Quarry Ceases Operations
The quarry ceased operations in 1941 and never reopened. The closing was due in part to new building techniques and materials as well as the halt in construction at the Cathedral. Today, the quarry is part of Yorktown’s 343 acre Sylvan Glen Park Preserve. 6.8 miles of trails wind amongst the abandoned quarry.
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- City of Yorktown, New York; Yorktown Trailtown Committee; yorktowntrailtown.org, Mohegan Quarry
- Milestone Heritage Consulting
- City Museum of New York, Digital Collections
- New York Public Library, Digital Collections
- Cathedral of St. John Divine Archives
