Denver Public Library

I spend a lot of time at the Denver Public Library. I think it rivals any other public library in the country. The collection is vast and the checkout terms are generous. The Central Library Branch is also an interesting place to visit for the stones it is made from.

The old wing, shown in these pictures is made from Salem Limestone from Indiana, and the dark green border on the bottom is granite reportedly from Austria. Here is a closeup of the green granite. Note the color is washed out because of the sun.

On the new wing there are two different types of limestone. The beige limestone on the south side of the library comes from the area around the town of Solnhofen, near Eichtstatt in Bavaria, Germany. This limestone is also used in the floor of the ground level floor. It is easy to see large ammonites, which are kind of like nautilus shells, coiled around themselves, and up to 8 inches in diameter. These fossils date back to the Jurassic era, about 150 million years ago. These fossils were formed when the critters died a lonely death in the muddy lagoons of long ago, when they swam into the wrong area and asphyxiated from a lack of oxygen. Their shells were buried and then fossilized.

The other limestone is found on the northwest
side of the building, and forms the trim on the floor.The green limestone is from Frankfurt, Germany and contains fossils as well. These are called belemnites, and they have spear-tip shaped shells. They are ancient relatives of squid and octopi. One library clerk told me that many geologists and naturalists visit the library to look at the floor just to see the fossils.

I walked around the library and found that the red surfaces and some of the green surfaces are just painted concrete.

The presence of the fossils, and the smooth surface of the limestone indicates what is true stone and what is concrete.

The base of the pillars is made from Stony Creek Granite, which comes from Massachusetts. It is a Proterozoic-age granite gneiss, and you can see the big crystals in the photos here. The white is quartz, the tan crystals are orthoclase
feldspar, and the black is biotite mica.

Directions (from RTD Plaza):

Turn right on Colfax.

4.3 left on Glenarm. Make a U-turn because of construction. Right on Bannock. Left on 14th Avenue.

5.1 Denver Public Library

RTD Plaza and the 16th Street Mall

I often ride the bus to work, and I usually pass the Civic Center Station when I do. RTD Plaza is the open area on top of the station, and it anchors the end of the 16^th Street Mall. The flagstones on the pathway are cut from two different types of granite.





The red granite is from Larimer County, and the gray granite is supposedly from Massachusetts, and the dark gray granite used to make these benches is from Minnesota.















Directions (from Colorado National Bank):
Continue southwest on 17th street.
3.7 right on Broadway
3.9 right on Cheyenne Park.
Park. RTD Plaza is behind you across Broadway

Denver Federal Court House and the bank.

On my way to work, I usually pass the Byron White Federal District Court House on 18^th and Stout. This building used to be the post office, but after renovations in 1992 it became the court house. The building is constructed from Yule marble, and the original marble had suffered serious weathering due to downtown air pollution. Since the Yule marble quarry reopened in 1990, all the panels were replaced and the building you see now is from marble that has only been exposed for 15 years.

The sculptures of the big horn sheep you can barely make out are made from Salem limestone from Indiana, a type of the famous Indiana limestone used to make the Cathdedral walls.

Just across from where I work is the former Colorado National Bank Building. This building is all Colorado Yule Marble inside and out, with the exception of the base of the building, which however, is some type of granite. The buildings look somewhat alike, don't they?

Directions (from Fisher Mansion):
Continue north on Logan.
2.2 left on 18th.
2.6 go to the right to stay on 18th street
Old Post Office
3 left on Arapahoe
3.1 left on 17th street
Colorado National Bank

Back to the map for downtown

Next we go into downtown, where the foundation of the area changes some. These buildings here are built on the Broadway alluvium, and for some, the foundations go down into the bedrock Denver formation. Deeper into the Denver Formation is a major aquifer. It is an important water source for communities not tapped into the elaborate Denver Water Board system.

Looking at the map again, we can see the change in color as we go from ‘ed’ to ‘asa’, which is the Broadway alluvium, and Broadway alluvial terrace.

This is a river terrace cut, and is the old flood plain of the South Platte. The boundary is pretty clear as you drive north along Lincoln just pass Cherry Creek. There will be a hill on your right side from there at Speer until you pass 20^th Avenue. The lower part of your left is the Broadway Terrace.

In the Denver area Broadway alluvium is about 6-12 mm thick and consists about equal parts sand and gravel. The gravel is made up of granite, pegmatite, quartz and small amounts of gneiss and schist, and there are beds of clay mixed in various places.

The next few buildings are built on top of this alluvium.

Fisher Mansion

Two blocks from the Cathedral, on 16th and Logan is a mansion that I find interesting to look at as I go to work. The Fisher Mansion is mostly made of an unknown sandstone. To me the yellowish color is unusual for Colorado.

The columns supporting the fence are made of Silver Plume Granite. This gray granite is one of Colorado’s oldest exposed rocks, at around 1,400 billion years old and is found near Silver Plume on I-70.

Here's a close up of the granite.

Directions (from Cathedral):

Continue north on Pennsylvania

1.9 left on 16th.

2 right on Logan

Fisher Mansion on southeast corner of Logan and 16th.

Cathedral of the Immaculate Conception

Our next stop is the Cathedral Basilica of the Immaculate Conception. This Catholic Church was built from 1902-1912 on the corner of Colfax and Logan. The outside of the building was built with Indiana limestone, which is a common building stone for monumental style buildings, including the Empire State Building. It was also used for the Episcopal Church just down the street. It is a freestone, meaning there is no grain or lines, so it can be cut in any direction, and be cut with a lathe.

The altar piece in the center of the photo is made
from Carrara marble from Tuscany, Italy.

This is the marble that was used for famous sculptures by Michelangelo and other Italian artists.

The trim in the rest of the chuch is made from Yule Marble, taken from the quarry near Aspen. Yule Marble was, long ago, merely Leadville Limestone, until the heat from Tertiary age intrusions in the Elk Mountains, were it is found, baked it into marble.

The base of the outside appears to be a type of granite from the Aberdeen Quarry in Gunnison.

Directions (from Milheim):

U-turn. Go north on Race.

.4 Turn right on 17th. Stop at St.Mark's for coffee and almond croissant.

.5 Turn right on Vine. Go south on Vine

.7 Turn right on Colfax.

1.8 turn left on Pennsylvania. Turn into parking lot on left.

Lyons Sandstone and the Milheim House

The next stop is just down the street at 1515 Race, which is the Milheim House. While made mostly of brick, it does have some nice sandstone trim.

This sandstone was called Manitou sandstone by builders , but geologists refer to it as Lyons Sandstone. This sandstone was quarried from Red Rock Canyon, which is just south of the Garden of the Gods. The quarry is now part of Colorado Spring Open Space, and you can hike around in the quarry and see where they cut the stone.

Here's a photo I did not take, and found on the web of Lyon Sandstone in Red Rock Canyon.

This layer of sandstone sits above the Fountain Formation, which I will write about later when we get to Roxborough State Park. Lyons Sandstone in the Colorado Springs area is about 176 feet thick, in a ledge that juts out of the ground. The size of the outcrop here allowed builders to cut big pieces for Denver buildings.

The layer was at one time horizontal, but now is almost vertical, as the entire layer was uplifted with Rocky Mountains and bent, in a ductile manner. This limb of a syncline was eroded away at the top, where it sticks out from the ground.

Here are the grains:

Both the Milheim and the Raymond Mansions are near St. Marks Coffeehouse, which I often visit for a fresh pastry.

Directions (from Castle Marne):

Go south on Race.

.2 Milheim on right.