Delta Slate Tour

SLATE - THE DELTA STORY

A HERITAGE TO BE PRESERVED

Tribute to the Delta Area Residents

The book "The River and the Ridge - 300 Years of Local History" can be obtained through the Old Line Museum, P. O. Box 35, Delta, PA 17314. Cost of the book is $35.00 plus $2.10 tax and $5.00 for shipping the thick book. Congratulations on the 150th anniversary of historic Delta!! The book is well worth the money with 300 pages, plenty of photographs and easy reading.

"Welsh Settlers of Delta, PA./Cardiff, MD" by Jack Jones and published by the Historical Society of Harford County, Inc. can be purchased for $5.00 from:

Jack Jones
243 Equine Cove
Red Lion, PA 17356
Tele. (717) 246-7100
Email: jonesgeo@comcast.net

Jeri Jones presented a paper at the 2005 Geological Society of America's Northeastern Section meeting in March on the history and heritage. Below is the abstract and reference.

Northeastern Section - 40th Annual Meeting (March 14–16, 2005)

Paper No. 14-2

Presentation Time: 8:30 AM-8:55 AM

THE PEACH BOTTOM SLATE IN SOUTHEASTERN PENNSYLVANIA - ONCE THE BEST BUILDING SLATE IN THE WORLD

JONES, Jeri L, Jones Geol Svcs, 276 North Main Street, Spring Grove, PA 17362, JLJ276@aol.com.

The Peach Bottom Slate (PBS) is found within a complex metamorphic terrain in Lancaster and York counties, Pennsylvania, extending into northern Harford County, Maryland. The formation is considered to be Ordovician in age, but its structure is still not completely understood. The earliest known quarrying of the slate goes back to Welshman John J. Roberts in the 1730’s. The first commercial slate quarry in the United States was opened in this area in 1785. In 1843, a large Welsh migration brought experienced miners into the area. With the introduction of the Welsh, a new technique of straight-walled deep surface mining was introduced. Approximately 34 quarries once operated within the PBS on “Slate Ridge.” At the 1850 World Expo in London, England, the PBS was voted the “best building slate in the world.” Uses for the slate included grave markers, shingles, sidewalks, windowsills, fence posts and stove plates. The slate has been used in many federal and state buildings as well as the Biltmore Mansion in Asheville, North Carolina. The final use of the slate in the 1930’s and early 1940’s was roofing granules at the Funkhauser‘s Quarry. Due to it’s higher than normal content of silica and aluminum, the PBS keeps its original color and does not weather. A local church has had a PBS roof on it for 200 years without any leakage.

(Click on any image below to enlarge it)

Delta, a small community in the southeastern corner of York County, Pennsylvania, is probably thought to be more closely associated with Baltimore, Maryland instead of York, PA. It was within this community, in 1851, that a "backyard" mineral resource would take this small, sleepy town into the center of stardom for slate. At the London Expo that year, the Peach Bottom Slate was judged to be the best decorative slate in the world. Many eyes focused their future onto Delta, including the Welsh, which actually started their migration to the area in the mid 1840's. With their knowledge on deep, straight wall mining from Wales, the Welsh educated the Scotish-Irish residents on extracting the maximum tonnage of slate from the quarries.

High altitude view of Delta (lower center) and Peach Bottom Atomic Power Plant and Susquehanna River along right side.

The Peach Bottom Slate District is certainly one of world fame. Although the discovery of the slate in Delta is credited to Welshman John J. Roberts in the 1730's, the first commercial slate quarry in the United States was opened in this area in 1785 by William Docher. All of the slate quarries were situated on the original McCandless property and later owned by the Williamson estate. Slate Point, located just south of the Peach Bottom Atomic Power Plant, is believed to be the location of the first quarrying in the area. John Cooper was the original owner of the property, but sold it to his grandson, Steve Thomas Cooper in the 1790's. Steve struck a deal with a John Kirk "to allowing the quarrying of slate for 99 years, at $.01/year until Kirk begins quarrying, $30/year for the first 7 years of quarrying, $60/year thereafter.” Although the history of these pits is quite scarce, it is believed that the slate was hauled by wagon to Peach Bottom, which is now the site of the atomic power plant. From atop Slate Point, which is owned by Philadelphia Electric Company, a great view of the Susquehanna River can be seen.

The role of a slate miner was a semi-skilled occupation. Wages were low for a ten-hour day, and the work was very hard and dangerous. Loosening the large slabs of slate from the vertical quarry walls while supported on a platform and removing to the sawer's shanty was risky. Not only was skill involved in being a miner, but also a lot of luck hoping that the machinery, tools or cables would not fail and cause a serious accident. Loosening the slate from the walls was not done by dynamite as originally suspected. Dynamite was too strong and would seriously fracture the rock. The lower-energy black powder was used to soften the blast, after which large wedge chisels were pounded into the fractures to slowly heave the slate block loose. The slabs removed were twelve feet by eight feet.

With the introduction of the Welsh in the 1840's, they brought with them the art of removing the rock working on a platform suspended by a cable and hoist. This method is what produced the vertical walls in the quarries and not having ramps and levels as you see in modern quarries. This was a dangerous way to work but allowed the maximum amount of slate to be removed for a particular operation.

Cables ran across the quarry. From these ran trolleys and with other cable rigging, the workers were able to lift the slab out of the excavation. Splitting the slate was another talent only mastered by a few. In 1929, 263,668 squares of slate were produced (Ashley, 1931, A Syllabus of Pennsylvania geology and mineral resources, PA. Geologic Survey, 4th. series, Bulleting G1).

The Jones Quarry as photographed in 1999. Pit is about 800 feet long, 100 feet wide, and 70 feet deep to the water elevation. Water is about 70 feet deep.

A waste pile at the Jones Quarry. Low quality slate and overburden was dumped here.

Slateville Presbyterian Church was organized in 1849 by a few members who separated from Slate Ridge Presbyterian Church. The cornerstone was laid on September 7, 1849, the date of the inception of the organization. Dedication occurred on June 8, 1850. In 1867, the congregation saw that the building was too small and built a new structure at a cost of nearly $7,000. This building was improved and renovated in 1884.

Notice the scribe marks. This is a testimony to the high quality of the slate.

The patience that Mr. Evans had in carving the markers was outstanding

Within their cemetery, the difference between the granite, marble and slate grave markers is quite noticeable. One problem that helped lead to the slate’s demise was that the slate was too durable to the weather. Engraving on the slate dating back to the late 1700's looks "like new" today. The life of a Peach Bottom slate roof is often 150 years. The colonial interior of the church includes the original stained glass windows, oak pews, and a Midner-Losch pipe organ which was installed in 1927. Carillon bells added in 1972 contribute to the music heard daily throughout the Delta countryside. The church celebrated their 150th anniversary in 1999. The church has been the "lunch stop" for the tours that Jeri Jones leads into the area, either through Jones Geological Services or with the York County Parks.

Notice the slate sidewalk, steps and church tower roof.

Slateville Presbyterian Church cemetery, a great place to inspect the Welsh language and slate engravings.

Robert E. Evans carved all of the gravemarkers in the cemetery. Oddly, his is a plain marker.

The Welsh families needed to settle someplace close to the quarries. Because the Welsh were a close-knit group, they basically did everything together. Along with their love to quarry slate, much of their social time was dedicated to two of their other loves: the church and music. The Welsh constructed vernacular style cottages in nearby settlements. The only remaining settlement of three is Coulsontown. The cottages were replicas of the miner villages found in the mountainous Snowdonia region of northwest Wales. Main Street in Coulsontown is about 600 feet long and gravel paved. Main Street today consists of a few vacant lots, several modern homes, a two and one half story framed cottage and four stone quarrymen's cottages. Cornerstones are large, well-shaped quoins. Door and lintel blocks are one single block. The walls are composed of the Cardiff Conglomerate, that’s found locally. Roofs are covered with slate. A distinctive feature is the four courses of cornice made of brick. Brick was considered a luxury item in Wales, thus the bricks here represent a symbol of their new economic status in America. The Old Line Museum has purchased two of the cottages and are currently are going through extensive renovation back to the 1850’s look.

A cottage constructed with the Cardiff Conglomerate. Walls are about two feet thick. Notice the double chimneys.

The largest quarry in the district is that of the the Funkhouser's Quarry. Once three separate operations, the quarries were combined, for a total length of about 1200 feet with vertical walls and water-filled. This was the site of the last slate operation in the area, shutting down in about 1944. The mining was extended northward by tunneling. The worst accident in the quarrying history of Delta occurred here in the early 1900's, when seven men were killed in a tunnel by a dynamite blast. The last products produced here were that of roof granules, although high-grade roof shingles were also produced. The product was hauled to the mill by railroad. Remnants of the mill can still be seen on the north side of Atom Road. Because of its easy access into the bottom of the quarry, this location has been a popular swimming area. Although the property is heavily posted with signs, Funkhouser's Quarry has been proclaimed by the U.S. Department of Labor, Mining Safety Division, as the second most-deadly quarry for drownings in the country.

View of the Funkhauser quarry looking southwest

Funkhauser's Company of Hagerstown, Maryland operated the last slate business in this once-famous district.

One cannot talk about the Delta area without including the Cardiff Marble Company, just south of Delta in Cardiff, Maryland. The site was famous for its own mineral resource, "Green Marble" or what geologists term a serpentinite. The greenish rock is a metamorphic rock consisting wholly of serpentine minerals commonly derived from the alteration of peridotite. In turn, peridotite is a coarse-grained igneous rock formed very deep inside the earth. The operation was originally a quarry being used for road construction, but in 1913, a blast exposed a piece of the serpentinite. The quarry sent the rock to Baltimore for polishing, after which it was determined that a new resource has been discovered. After changing their equipment to concentrate on the beautiful rock, rapid expansion of the quarry started. At the completion of the operation in the early 1970's, the shaft extended to a depth of over 300 feet with numerous tunnels at various levels. Huge blocks of the serpentinite were lifted out by horst and cable, similar to the slate operations, and removed to the saws in nearby buildings. The rock was used for decorative stone, lamp bases, table tops, fireplaces, and desk ornaments. The rock was used as decorative stone in the Empire State Building in New York City, the Department of Highways Building in Harrisburg, along with the bottom of the walls in City Hall in York, PA and in numerous federal buildings in Washington, D.C.

Horst and cable device to raise large slabs of the serpentinite out of the shaft as seen in 1999.

Cart used to transport the rock
through the saw.

Vertical shaft as it appeared in 1999.

So, what has happened to the heritage of the Peach Bottom slate industry and the Cardiff Marble? Due to the efforts of many of the residents who grew up in the community, the heritage is stronger than ever.

As I found out when organizing my first fieldtrips there and continue to see, area residents love to talk about the heritage. The Old Line Museum in downtown Delta is a great way to discover the heritage. Filled with artifacts, photographs and clothing, a visitor can quickly find themself living in the 19th century. The museum is also home of the world-famous "Slate Clock", a one-of-a-kind creation, made by Humprey O. Pritchard, a life-long slate miner. The clock stands seven feet and two inches tall, thirty inches wide and over one foot deep. Three different slates were used in the production of the clock: Peach Bottom deep blue slate, Bangor, PA silvery gray slate and red slate from Vermont. The museum is open Sunday afternoons, May through September from 1:00 - 5:00 pm and by appointment. Email them at oldlinemuseum@aol.com.

World famous slate clock

The geology of the Delta area is still one of those mystery areas. The first research conducted by George Stose and Anna Jonas in 1939 mapped the area as being a syncline, with Peach Bottom Slate in the middle, and the Cardiff Conglomerate and the Peters Creek Formation scists laid on the limbs of the fold. Since the Cardiff Conglomerate is absent on the northern limb, Stose and Jonas placed a fault along the north side, between the slate and the Peters Creek Formation. Other researchers who mapped in the area saw evidence for an anticline and not a syncline (Michael Higgins from the U.S. Geological Survey, among others). The most recent research was conducted by David Valentino, who at the time was employed by the Pennsylvania Geologic Survey, and he could not determine what type of folding was involved and proposed the name "Peach Bottom Structure" to the fold instead of the "Peach Bottom Syncline”. With the complex geology and limited outcrops of bedrock (obviously most of the slate is exposed in vertical-walled quarries where one cannot look closely at the structure), the formation of this area is still debated by geologists.

Because of the lack of fossils and the amount of folding in all of the formations within the Uplands Section of the Piedmont, the Peach Bottom Formation has been assigned an Early Paleozoic Era date.

Map of Stose and Jonas (1939) showing the Peach Bottom Formation (red).

Finally, it was discovered in the late 1970's by amateur mineral collector, Donald Schmerling, that gold occurred in several of the streams in the area. Today, about 15% of streams in York County contain gold. Although gold has not been found in place with bedrock, panning within several of the slate quarries did produce gold. Several other good localities include the Delta Fish and Game Club along Peaks Peak Road, along the same streams further north where they intersect with Muddy Run near Castle Fin, and in Robinson Run, north of Delta. To the west of Delta, at Constitution, several small streams have produced gold and nice crystals of rutile. The largest gold found in this area is about 0.75 inch, apparently associated with the Peters Creek Formation schists.

Dark lines in left center (above "BO" in Bottom) and along the right top side of map represent streams that contain gold north of Delta.

Large Mills Quarry; K - Lloyd Quarry; L - Stewart Quarry; M - Electric Quarry; N - Edwards Evans Quarry; O - John Williams Quarry; P - John Humphrey Quarry; Q - McLaughlin Quarry; R - A small un-named opening; S - Faulk Jones Quarry; U - Johnson Quarry; V - R. L. Jones Quarry. Bold represents quarries that were combined to produce the Funkhauser Quarry. The belt extended into Maryland for a distance of 1.5 miles and into Lancaster County for about 5 miles. The entire slate area is only about 0.25 mile wide. The dark line crossing the map from the lower left to the upper right represents the proposed fault between the Peach Bottom Formation and the Peters Creek Formation. Hashed boundary on south side of slate represents the approximate contact of the Peach Bottom Slate and Cardiff Conglomerate.

The Rehobath Welsh Church is one of only three such congregations in the United States. Weekly services are still held here in the native language. Two Welsh Hymn Sings are held in May and October respectively.

The Rebobath Welsh Church

The original Delta Jail is built out of the Peach Bottom Slate. The walls are 18-inches thick. Many of the slate blocks saw the saw marks. Even this building is well maintained to preserve the heritage of Delta. No, the author didn’t do anything wrong to be behind bars, just the creative idea of his associate.

Delta Jail made of slate