Category: StreetSmartNaturalist

Good Old Cobblestones

President Obama has said that his stimulus plan will provide the “largest investment increase in our nation’s infrastructure since President Eisenhower created the national highway system half a century ago.” It will create hundreds of thousands of job for people rebuilding railways, bridges, and roads. While I applaud his concern about jobs and improved safety, I worry that in the mad rush to pave we may lose a bit of history—the handful of cobblestone roads still dotting Seattle.

A happy group of explorers trodding across one of Seattle’s last cobblestone streets

Between the 1890s and 1910s, sandstone cobbles were a a popular road-paving material in Seattle. The most commonly used varieties came from quarries in Wilkeson, a small town about 45 miles south of Seattle. Workers could easily cut the brick-sized blocks, which provided good traction for horses, although horse shoes did wear down the stone. And the stone cobbles lasted longer and created less of a mess than the mud or wood of the past. (Manhattan also has a few cobblestone streets made from the 450-million year old Quincy granite.)

Quincy Granite cobblestones in Greenwich Village

The Wilkeson sandstone lithified from thousands of feet of sand deposited 40 to 50 million years ago in the Eocene Period when western Washington was flat and subtropical. Palm trees, swamp cypresses, and tree-sized ferns grew in the moist (40-100 inches of rain), bayou-like environment. Waves from an ocean that spread to the west washed ashore on beachfront property, now covered by the urban metropolises along Puget Sound. The only mountains that existed rose far to the east along the Washington-Idaho border. Rivers and streams washed out of those mountains and dropped sand in a coastal lowland dotted with seasonal lakes, swamps, and lagoons.

In addition to sandstone cobbles, brick was another important paving material and can still be found on a few Seattle streets. Local manufacturers used a clay deposited in a proglacial lake, which formed in advance of the ice sheet that covered Seattle during the last Ice Age. A production capacity of 70,000,000 bricks a year made King County the largest producer of paving brick in the country. At one time, these bricks covered streets in Portland, San Francisco, Tokyo, and Los Angeles, as well as roads in Chile, Argentina, and India.

One other local building material, the Index granite, appears on local streets. It formed 34 million years ago during subduction of the Juan de Fuca plate under the North American continent. The Index was used primarily for curbs and can still be found in a few older neighborhoods of Seattle. (One way to get a feel for the age of a neighborhood is to look at the curbs. Old ones are granite; newer ones have concrete with a metal rim, particularly on corners; and modern ones are only concrete.)

According to the last official survey I could find, conducted in 1993, only 93 of these historic streets remain in Seattle; most have been paved over, their stories lost to drivers who don’t want the jarring ride. I do not mind them. I like the connection to the past and consider it a privilege to drive over the ancient cobbles and rustic bricks, although I try to take these roads when no else is in the car with me.

Building Stone Census of 1880

Every ten years the federal government conducts a census of the people. Census takers spread across the country ferreting out the vital statistics of America. For the 1880 census, the government also took stock of building stones and the quarry industry. I was recently lucky enough to acquire a copy of the 410-page report. (It came to me because my brother-in-law bought a bar in Arizona, which had the book in it, and his seven-year-old son was kind enough, with a bit of coercing, to give me the tome.)

As one might expect of a census, the book provides a minutia of facts. For example, 1,525 quarries operated and generated 115,380,133 cubic feet of stone, roughly enough to build one and a half Great Pyramids. Or you can learn that a David Williams owned a slate quarry in Slatington, Pennsylvania. The quarry was in Lower Silurian beds, produced black slate for roofing and school slates, and opened in 1864. Sounds like an industrious fellow.

Of more interest is the section that describes the building stones used in 137 cities, ranging from Akron, Ohio to Zanesville, Ohio. The listings reveal the classic story of most cities and towns, which generally use local stone, if available. Some people also import outside rock, most often for monumental buildings such as banks or churches. The story changes slightly in the bigger cities of Boston and New York, which still use local rock but also pull in stone from around the world. For example, exotic marbles came from Italy, France, Portugal, Switzerland, Spain, and Germany. That being said, 80 percent of the stone fronted houses in New York City used brownstone, most likely quarried in either Connecticut or New Jersey.

A hornblende granite from Grindstone Island in New York, some of which was used as paving material in Chicago

Reading through the census book, I am reminded of other books like this. These are the older scientific books that seemingly attempt to put in everything known about a subject. They are clearly labors of love of the writer and detail not just the science but also the history of a subject, such as the origin of a name of a species or who first used a particular building stone. In delving so deeply into the finer points, the authors make their subjects so interesting that the reader cannot help but take a deeper interest.

A channeler, used to cut stone into blocks in the quarry

Perhaps that is why my new book from 1880 survived its long life at a small bar in the middle of nowhere Arizona. I like to imagine that the drinkers of yore gathered around the book late into the evening and regaled each other with the many fine facts. I am sure they were better people because of what they learned.