As the university became wealthier, it no longer had to rely on local rock. From 1913 through 1915, architect Horace Trumbauer and his chief designer, Julian Francis Abele, oversaw construction of Harvard's great sanctuary of books, Widener Library, using a buff limestone from Indiana quarries for the foundation and columns. Packed with bits and pieces of information, Widener's building blocks house the University's most accessible fossil collection of marine shells.
These fossils occur in blocks of the 330-million-year-old Salem Limestone, a rock unit that formed in a warm, tropical sea. At that time, most of the land mass now known as North America lay south of the equator. Shallow, clear water covered the area that stretches from present-day Nebraska to Pennsylvania. A myriad of organisms swam and crawled about this placid sea. When they died, their bodies settled to the sea floor, over time solidifying into a 90-foot-thick stone menagerie. This homogeneous matrix of corpses formed a rock that cuts cleanly and evenly in all directions.
Wave action from long-still tides shattered most of the shells, but many organisms persist and stand out. A unicellular animal known as a foraminifer, which lived in the ooze and muck of the sea floor, is common in this limestone but hard to see, even with magnification. Dotted throughout the walls, and easily discernible, are the poker-chip-shaped stems of crinoids, an extinct relative of starfish, and half-inch-long bryozoans, a sedentary animal that formed colonies of Lilliputian-scaled apartment complexes patterned like Rice Chex cereal. Many shell fragments come from pelecypods, the group that includes oysters, clams, and scallops. A rare find is a perfectly formed half-inch-long snail shell, which resembles a tiny swirled dunce cap.
Salem Limestone is one of the most commonly used building stones in the world. Over the past century, quarries in Indiana have sent this stone to the Metropolitan Museum of Art, Empire State Building, Grand Central Station, Dallas Museum of Fine Arts, San Francisco City Hall, and innumerable buildings in cities and towns from coast to coast. Other Harvard buildings that use Salem Limestone include the Gunzburg Center for European Studies (formerly the Busch-Reisinger Museum), Lowell Hall, and Langdell Hall.
Logging Requirements
1. What color is the limestone? How does it feel?
2. Do you see any fossils in the foundation or on the columns?
3. Why do you think Indiana limestone was used for this building?
4. Do the carvings show any type of erosion?
5. Post a picture of yourself (face not required) or a personal item with the limestone.