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They show no disintegration or decay and retain the strong, brilliant, blue-black color for which this slate has become famous by the name of Peach Bottom. The seventh building was reported to be a hog pen located near Delta, PA, and still standing in 1930. It is reported in The Stone Industries 1934 that a sample of this slate was rescued and is now on exhibit at the United States Bureau of Mines in Washington, D.C. After nearly 200 years of service, it shows no evidence of deterioration.

One of the first roof replacement slate roofs made of Peach Bottom slate was laid by Joseph Hewes, a signer of the Declaration of Independence. The first commercial quarrying began around 1785 by a fellow named William Docker, but quarrying didn’t get into full swing until the Welsh stepped into the scene in large numbers around 1845. In 1848, about 30 Welsh people arrived in Philadelphia en route to Peach Bottom to become slate quarries, splitters, blacksmiths and stone carvers.