A tour of Woodlawn Cemetery in the Bronx, N.Y., focuses on the geology of the landscape and the mausoleums.

Steve Mirsky:    Welcome to Scientific American Science Talk and happy Halloween. [menacing laughs] In the spirit of spirits, we'll take a walking tour of one of the great cemeteries in the United States. Woodlawn Cemetery in the Bronx, New York, where more than 300,000 people do not live including Duke Ellington, Miles Davis, Herman Melville, F. W. Woolworth, Fiorello La Guardia, Bat Masterson and Joseph Pulitzer.

                           But since we're science people, our focus is gonna be on the geology, especially that of the rock used in the more than 1,300 opulent mausoleums at Woodlawn Cemetery. And we'll get some culture, too. You'll hear the voice of Susan Olsen. She was the executive director of the Friends of Woodlawn Cemetery when this was recorded and you'll hear the geologist Sidney Horenstein.

                           This tour actually took place in 2008 and I put up much of the audio for Halloween 10 years ago. But here's a slightly revised version. And now, let's go hang out at a cemetery.

Sidney Horenstein:    The most prominent stone is the one that you're standing on right here and this is from Milford, Massachusetts. That's about 350 million years old and you probably – all of you have seen it because it's the main entrance of the Museum of Natural History on Central Park West. It's the same stone. Unfortunately, there they tried to clean it several years ago and they used hydrofluoric acid to clean it so it's bleached white. But it's beautiful pink granite. IF you wanna see what the original color of the stone was at the museum, look at the benches. they didn't clean the benches. Those are the original pink-colored sheets. You can actually contrast it.

This is slate and slate is a metamorphic rock. Here's the whole transition that you might be familiar with. Mud bath forms on the seafloor. The sheet gets hardened to shale. When shale is subjected to heat and pressure, it becomes slate. When you then add more heat and pressure, it becomes phyllite, a rock that you don't see too often that you may not be familiar with. And then, when you add more heat and pressure to the phyllite, you get schist. And everybody's more or less familiar with the Manhattan schist. And then, if you add more heat and pressure, it melts and becomes an igneous rock.

Susan Olsen:     One of the things that's astounding to me, though, is of course how so many of our wealthy New Yorkers decide to treat us, the little people, to their travels. And we do have a wealth of Egyptian things. Our Egyptian things traditionally date to around the time when they're excavating King Tut's tomb. Egypt-o-mania hits New York, everybody's crazy about it and I remember in the '70s when King Tut toured and we all were wearing our little pharaoh earrings and that kind of thing. Same thing but this one, of course, dates 1916, a little bit earlier.

Jules Bache, well known as a stock broker, goes to Egypt and of course he's so inspired as he gets there that he decides to recreate his own tomb.

Horenstein:       What is a tomb? It's the Kiosk of Trajan. There it is, in its setting. That's its exact reproduction of it except for one thing, which I'll explain to you in a moment. This is no longer in the original spot it was built in because of the Aswan Dam and the rising waters of the Nile. It was moved. It was the entryway into a temple complex and so, here it is.

And so, you see – what do you see? Just a few of the motifs. You see, up at the top, you see the vulture wings. That's maternal aspects of life. The sun is life. The snakes, the asps, go as a pair – death. See, and one of the reasons why Egyptian architecture was so important in cemeteries is because of the fact that it was so involved in death. There's a lot of interesting motifs that are reproduced. There are papyrus leaves, also, mixed in with the lotus and those represent knowledge and rebirth. All kinds of symbolism that's involved in it.

Now, the Egyptian Revival architecture. There were three periods of Egyptian Revival architecture. The first one occurred when Napoleon invaded Egypt and it was a tremendous flurry of interest in that. And then, there was another one in the 1840s and 1850s. And for example, if you go to Mount Auburn in Massachusetts, the entryway there, that is an Egyptian Revival.

But we had a lot of  Egyptian Revival architecture in New York. The Croton Aqueduct Reservoir on 42nd Street. The tombs downtown on Center Street, no longer with us. Egyptian Revival. And of course, in terms of Egyptian Revival, we don't think about that but on the dollar bill. That's all part of it, see? The pyramid. And you see that, see?

Interesting place. And where does this stone come from?

Olsen:                It comes from Barre, Vermont.

Horenstein:       Barre, Vermont.

Olsen:                One of the things is that a lot of the stone types that are selected are based upon trends. What people were building downtown, what was the fashionable color at the time as well as certain vendors or architects. They were hooked into this quarry. Farringdon, Goulding and Hoagland is the monument firm. You'll see their work across the street at Gates, Woolworth, et cetera. They always get Barre granite. Everything they build is always done out of the same stone.

Horenstein:       An exciting place. If you ever get up there, go on a tour. You'll have a good time.

Olsen:                And the cemetery there is crazy because all the monument makers decide to do their own custom things so the cemetery has got some of the most fabulous distinct and unique memorials you'll ever see.

Audience:          Sidney, the original in Egypt. Was that limestone?

Horenstein:       The original was limestone. The Mokattam limestone, which is 40 million years old. I'm glad you said something because I said there was – this is exact reproduction except for one thing that's there and not here. And guess what? The most studied part of the original monument is graffiti. There is graffiti going back hundreds and hundreds of years that people who came there, it was a great place to visit. They left hearts, initials, everything and people have studied this year after year trying to figure out who left their mark. It's all full of graffiti but fortunately there's none here.

Mirsky:               You've heard of the Juilliard School. We next stopped at the Juilliard mausoleum.

Horenstein:       This is a pink granite from North Carolina You can see that it's a little coarser than what we've been seeing. The minerals really stand out, the black mineral. There are two black minerals in granite. One is biotite mica and the other one is hornblende. And the darker the granite, the more hornblende and biotite mica there is.

Now, one of the interesting things about the various Greek and Roman architecture is here. Ionic, Corinthian and Doric are the three main ones. Tuscan is stripped down Doric. The Romans and the Greeks actually used things from nature to signify, to make their designs. For example, the volute, the eyes in the Ionic. Those are if you pick a snail – many snails – and you cut it open, slice it in half. You'll see the curve of it. But what happened was an interesting thing.

Vitruvius, who first documented all of the various Roman and Greek motifs in architecture, said anthropomorphized many of the architectural elements. And so, he said Corinthian columns represent God. And Ionic columns are feminine. And Doric columns are masculine. And so, many of the mausoleums have an Ionic entrance because it's feminine. And so, you're reentering the womb. And then, of course, the volutes actually represent pearls of hair, public hair. They've extended this. And since all architects studied Vitruvius in the past to get all the design elements, they have carried that forward. And so, it's an interesting aspect of the architectural and the meaning of some of these things.

Mirsky:               Here's the resting place of playwright Clyde Fitch.

Olsen:                It is 140 pieces of marble but there was someone on a tour who loves Clyde Fitch plays – has anyone ever seen a Clyde Fitch play? Anyway, there's one guy out there who loves them and donated $30,000 for us to restore this one wonderful piece. On our list, it's killed Knoxville Gray but Sid will be able to give you a little bit more understanding about this Tennessee marble.

Horenstein:       Tennessee marble is farmed during the Ordovician period. It's the same age as the Inwood marble. During the beginning, before the Appalachian Mountains existed, there was this interior seaway that extended from Vermont, Vermont marble, all the way to New York and all the way down to Alabama. And in that sea was deposited lime.

Remember that limestone in which this is limestone forms only in tropical and sub-tropical seas. And so, whenever you see – if you see limestone or marble in Vermont, you know that that originally formed in a tropical or sub-tropical sea in the past. And of course, in North America, was really south of the plate for some time or even equatorial. And then, because it's a sea and different environments in that sea, the different types of limestone that's formed.

And so, Knoxville was the marble capital of the world. Knoxville has many, many different types of limestone that are called "Tennessee marble" but it's, as we know now, it's really a limestone geologically, not a marble geologically. And so, there's deep-cedar red, Knoxville fluoride, all different types of limestone in this vast quarried district around Knoxville. And if you wanna see it elsewhere, the floor of Grand Central is pink Tennessee and the lions in front of the New York Public Library is another – not marble – limestone from Tennessee also.

It stands up very well. These are all fragments of fossils in here which are hard to see but there's been a little alteration in the rock. but they're all little, tiny fragments of it. In some places, it's better than others and so you can see that. Other places, you can see the fossil more clearly. Of course, if you go to Grand Central and get down on your hands and knees and look at the floor, they may not think you are too cool there.

But anyway, another thing we should mention is the sarcophagus. See, usually the people are not buried in there. They're underneath. But it's so symbolic. And the interesting thing about that is the word "sarcophagus." Sarco, you know what sarco means? Flesh. And phagus means eat. The sarcophagus was a place where flesh was eaten, but why? Why would that happen?

Well, the original sarcophagi were made of a kind of sandstone that was very caustic and the name stuck. It has no relationship to the present time and there was that peculiar sandstone that did that originally. And that's why. It continues. It's a misnomer today.

Olsen:                One of the things that happens at Woodlawn is the price of the lots. If you're Cornelius Bliss on the corner there, you paid a little bit more 'cause you were on the intersection of the road, you're really in the star situation. His daughter gives us the Museum of Modern Art. His grandson gives us Texaco and the opera on the radio so the Bliss family is good. 

Anyway, circular lots were more expensive. Cross-lots were more expensive. But what was surprising to me is if you bought a rock outcropping, that cost even more. You would think it would be cheaper 'cause you can't bury where the rock is. But because you had the opportunity to do a fabulous design, you paid more. Reason constables wanted here? For them, it was not the monument that was the memorial but the landscape. They get the Olmsted brothers to do their landscaping where, along here, many of these families brought their own landscape designer. It was an ideal spot. Now, why is there a rock outcropping? I don't know.

Horenstein:       Because the bedrock came to the surface. Here. Which reminds us that Woodlawn, it straddles sort of the top of the Bronx and the bedrock is not too far below the surface covered by glacial deposits and lots of boulders. Probably, if you would dig down, you would find a lot of boulders but it's on the, straddles the top.

And so, back there, there's a small ridge and that is the continental divide of the Bronx. And what that means is that it's a drainage divide. And for this side, all of the streams that used to exist here flowed down, eventually into the Hudson River. On the other side, where do they go? Into the Bronx River, see? And that goes into the East River. This is an interesting place from that point of view.

Now, the bedrock itself if the Ford of Gneiss, which is the oldest rock New York City. It's $1.1 billion years old. Gneiss is a type of metamorphic rock and a lot of the Bronx is made of it. That's why we talk about the Bronx being gneiss or Woodlawn being gneiss and that Manhattan is full of schist.

Olsen:                Now this one I know is pink marble and not granite.

Horenstein:       And it's Knoxville pink marble, which is actually a limestone. You very clearly can see the layers in the limestone.

Audience:          Do they match?

Horenstein:       It was actually layers but it has another feature. And these are called stylolite. It's this zig-zag feature that you see in here. Looks like a seismogram record. And what they are is that when this limestone was laid down, in layers, there was a lot of pressure on it. And there was, as a result of the pressure, there was dissolving away of some of the calcite, the mineral that limestone is made of. And the, redeposited later in other parts of the rock. That's what gives the rock its stability and its strength. And the stylolite are solution features. And they're black because every rock is not pure, it's not pure calcite. There's other minerals in it and there are clay minerals. And so, as the calcite is dissolved away, it leaves a residue of clay and it gets concentrated along the lines where the dissolving is taking place. And so, that we know this is limestone because if it's metamorphose, it becomes geologic marble. The stylolite are destroyed during the recrystallization of the rock.

Olsen:                You'll see just all of a sudden a ton of obelisks everywhere. You get to show off that you're rich. You get to show off this great monument. But you still want to be in the ground. And that's' why.

Also, when Sid and I were practicing, we were like, "Are those identical? Are those different? Are they –" there's always a little bit of difference. We did not let you be identical to your next door neighbor. You had to present the image to us beforehand. We'd look at your design an make sure it was appropriate for the lot, appropriate for the neighborhood and wasn't identical to who was around you because this whole, overall look was extremely important to us.

Also, somebody's asked do we give tours? Yes. Woodlawn gives regular tours. one weekend it's jazz. One weekend, it's theater. One weekend, it'll be art and architecture. Sometimes it's specifically sculpture. Last weekend, it was the Piccirilli brothers, the six brothers from the Bronx who carved the Lincoln Memorial. They also carved that little pink angel across the street.

Audience:          That's beautiful.

Olsen:                They did that for Daniel Chester French, the guy who did the Lincoln Memorial. We've got lots of custom sculpture out here but of course, those six brothers from the Bronx were the guys who carved everything. I can find their monuments like that [snaps fingers] because now I know what Tennessee pink is and they always carve in Tennessee pink. It's their preferred stone type and so it's real easy to pick out a Piccirilli.

One of Sid's favorites is this one. Foster is Foster's Fascinators. He made snap for gloves. All you've got to do is come up with that one thing everyone needs and you're a millionaire after that. What tickles me about the monument – it was done in 1895 – is that on this side, you see this very flashy signature. And I always think of when you're a little kid. And you start out in school. And you're first learning cursive writing. And if you go on the other side, you see his wife Bertha's signature. Bertha.

[laughter]

                           Foster had the flair in this but it's got so much stone going on. I want Sid to tell you what he's discovered about Foster.

Horenstein:       First of all, it's an interesting structure because it's actually a sarcophagus with a canopy up, over it. A tent. But the tent happens to be in stone. And the granite is very distinctive, as you can see, pretty much not with any blemishes. We're gonna talk about that in another place. Some granites have blemishes in it.

But you can see up here, the white material and look at it on the column over here, you can see it coming down. And that is called efflorescence. We have a structure that is now has water infiltration and what it's doing is the water is infiltrating into the joint system and dissolving out the water. And then, when it comes out on the surface, the water evaporates and then deposits the lime on the surface of the stone.

It's not a good thing because it's disappearing. I mean, that's why the West Side Highway collapsed, for the same reason. Of course, all the concrete was being dissolved away and they had tremendous stalactites forming. And so, flowstone – which that is called, is very similar to stalactites. Stalactites come down from the ceiling, this comes down on the side of the wall but it's the same process that forms not only in buildings and structures. But also in caves.

While we're here, Susan mentioned the obelisks so here is an obelisk that was just finished in the quarry, put on. it's going to be put on the railroad and carried to Woodlawn. See? See that?

Audience:          Cool.

Olsen:                And of course, the obelisk becomes really popular when two things happen. Washington monument gets finished, Cleopatra's needle. Good enough for Central Park, good enough for Woodlawn. And that's when you see this flurry of obelisks all over the place.

Horenstein:       And you know what the obelisk represents? It represents a ray of sunlight and then of course the Egyptian obelisk always had a gold cover at the pyramid at the top to catch the rays of sun and be transported down. But it's a ray of sunlight.

Mirsky:               Our next stop was at the tomb of naval architect William Webb.       

Olsen:                – made an extraordinary fortunate building ships, the fastest ships, from timber ships to early steamships, et cetera. Leaves his entire estate to create the Webb School of Naval Architecture. The Carrara marble from Italy, which Michelangelo carves David in, a lot of our interior work – although some of the outside works – have this very soft, light marble.

Horenstein:       And so, Carrara marble comes from Mt. Altissimo. And this is over 5,000 feet high, slowly disappearing. It's a real – when the trucks come down the roads, you get out of the way. Let me tell you this. And its' a phenomenal place to see. But just keep in mind that this marble is called statuary marble. And statuary marble is pure marble. There's no veins in it. There's no imperfections and that's very rare. And they're finding less and less of it in Carrara.

Also keep in mind that the cheapest marble, it's called Italian gray marble, comes from Carrara also. It has a cache to it but it's not – the various kinds of marble that are located in it. And it is true marble. It is not limestone.

Olsen:                A lot of the new monuments we have, some of you have asked about the jazz section. In the jazz section, you'll see some really big, black monuments. The new technique of putting your picture on 'em is to computer scan and then sandblast so that you can be Illinois Jacquet with a nine-foot statue of you playing the saxophone. But to do this, you need to use a dark-colored granite. It won't work on a light granite. And most of this stuff comes from India today.

But back in the old days, it didn't come from India. We wanted to stop here to show you some  of the distinct, darker granites that you'll see. This is William Buckingham Curtis, the founder of the New York Athletic Club.

Horenstein:       This stone is dark Quincy granite. Quincy granite was a large quarry area just south of Boston and it had varieties of different stones. And the one that was the most desirable and the most expensive was dark Quincy. And it had a problem. You can see that some of the feldspars are turning to clay. It's called kaolinization, like kaopectate. Kaolin, same thing. And so, that's what happens to the feldspar minerals.

But it really went into tremendous decline when they discovered that they were doctoring the stone. They were taking oil and carbon. And rubbing it into the stone to get it dark. And eventually what happens, it starts to wear away. And then, when that was discovered that they were doing that – it got lighter, it got splotchy. No one would allow Quincy granite to be used, dark Quincy granite to be used anymore.

And so, it went into quarries basically closed up as a result of that. This happened in the 1930s when they were desperate to get more business. And today, you can go to Quincy and see many of the old quarries. Many buildings in New York City are made of Quincy granite. The first commercial railroad in the United States was built to take Quincy granite from the quarries to Boston to build the Bunker Hill Monument, 1821.

[audio gap]

You have a whole bunch of – this is a granite from New Hampshire. Some of you may have seen the film The Fountainhead and they worked in the Fletcher quarry. That's the stone here. New England is just so richly endowed with so many varieties of granite. Different colors, different textures. And the things to remember about granite, it is a rock that forms six, eight, 10 miles below the surface of the Earth. And that's where it cools. And that's where it crystallizes.

And so, when you see granite where you can quarry it on the surface, this means that the crust of the Earth has risen upwards. And all of the overlying rocks get stripped away by erosion over millions of years to expose that granite. Anytime you see granite anywhere in the world, it's a testimony to the dynamism of the Earth.

[audio gap]

                           One of the other things I want you to notice is for example that column there, about halfway up – a little less than that – you see a black mark. you see it?

Audience:          Mm-hmm.

Horenstein:       And then, up there. And then, over here. All around. And these are called xenoliths. Xeno, X-E-N-O. Xeno means foreign like xenophobia. Xeno-foreign rock. And what this is, remember that this is molten rock. And so, as it's forming in this chamber, it's reacting with the sides of the huge chamber. You're talking about huge, massive material. Pieces of the sides fall into the molten material and they get dissolved usually. But sometimes, they don't. And they remain. And they don't get completely dissolved away. And so, those are the xenoliths. These are part of the chamber walls that have fallen in and still remain. And that's why they're called xenoliths. They're foreign to the molten material itself.

Mirsky:               We continued onto the Harkness Memorial Garden.

Horenstein:       And notice that the stone that's used in the actual structure sort of matches the bedrock. The bedrock is the ford of gneiss. And you can see the layers all running in the direction of my hand here, going this way. But the stone itself is unrelated to it. It's not gneiss, metamorphic rock. It's actually a dolomite.

Now, dolomite is somewhat related to limestone. The basic composition of limestone is calcium carbonate, the mineral calcite. However, magnesium easily substitutes for calcium so when you have a calcium magnesium carbonate, you have now the mineral dolomite which is what that is. But it also has, as an addition, iron oxides. And the iron oxide is what gives it the various shades of brown to tan. And so, it is still acquired today. A lot of it is used for flooring. It's very durable because it's not soft, like calcite. It's dolomite and so – but it has a lot of holes in it because of the way it was deposited.

Olsen:                Let's thank Sid.

Horenstein:       Let's thank Susan.

[applause]

Mirsky:               For more info, Google "Friends of Woodlawn Cemetery" and check out Sid Horenstein's books including A Geologist Looks at Manhattan, Rocks Tell Stories and with co-author, renowned evolutionary biologist Niles Eldredge, Concrete Jungle: New York City and Our Last Best Hope for a Sustainable Future.

That's it for this episode. Get your Science News at our Web site, www.ScientificAmerican.com where you can hear a 60-second science podcast about the tiny insect that pollinates cacao trees, without which, no Halloween chocolate. And you'll follow us on Twitter, where you'll get a tweet whenever a new item hits the Web site. Our Twitter name is @sciam.

For Scientific American Science Talk, I'm Steve Mirsky. Thanks for clicking on us.