Ammonitic Limestone: Prehistory Meets Ancient History in Verona, Italy
Millions of Years Under Your Feet in the City of Romeo and Juliette
While vacationing in Italy, my husband and I spent several days in Verona. While we expected to see a lot of ancient and early modern history in the art and architecture of the area, we were surprised to find evidence of prehistory in places we least expected it: in the sidewalks, steps, and walls of the city.
Walking along a narrow street one day, I looked down to see a familiar spiral or Nautilus shape embedded in the smooth stone. I recognized it from a necklace I have, though my pendant is much smaller than what I'd just stepped on. It was an ammonite -- the fossil of a cephalopod, which originated sometime between 65 and 400 million years ago when these mollusks existed.
Once we noticed that first ammonite, we began to see them all over the city, most quite large and some huge, not only in the sidewalks but also in the walls of old churches and other stone buildings and even the ancient Roman colosseum. I'll show you some of them below, along with an abandoned quarry where much of this limestone came from.
Photo credits: Unless otherwise noted, all photos on this page were taken by me, Deb Kingsbury.
Ammonites in the Arena Di Verona Coliseum - The Cretaceous Period meets 1st Century A.D.
The photo above is part of the Roman arena at the center of Verona, constructed in the year A.D. 30 and used for a variety of shows and games of sport and skill, with spectators coming from near and far. During those events, the audience would sit on rows upon rows of stone blocks -- limestone blocks, that is -- many of them containing ammonite fossils.
Before we learned that the location of the fossils was random within the arena, we thought perhaps they marked special seating. Like reserved seats maybe for certain people. But, no, apparently they just happened to be in those blocks.
The Colosseum Today - Modern mixes with ancient and prehistoric times
Where did they come from? And why are they so big?
Called "nodular limestone of Verona," this fossil-filled rock originally formed at the bottom of the Tethys ocean which once separated the mainland of what we call Europe from the Adriatic microplate.
The swimming mollusks that created these spiral-shaped fossils were actually related to soft-bodied creatures we're familiar with today, like octopuses, squid, and cuttlefish. But the ammonites and their closest relatives became extinct along with dinosaurs at the end of the Cretaceous Period about 65 millions years ago, and the shells containing their invertebrate bodies settled at the bottom of the ocean.
As far as size, most of the ammonites that existed up through the middle part of the Jurassic period (roughly 160 million years ago) were small, rarely reaching as much as 9 inches in diameter. Much larger fossils have been found in the rocks formed in the later part of the Jurassic and early Cretaceous periods.
I'm no geologist, but from the sizes of the fossils we saw embedded around Verona, I would say many of them fit the description of ammonites from that later Jurassic/early Cretaceous time. While some of those around the city were maybe six inches in diameter, many that we came across were a foot or more wide.
More Fossils in the Walls and Sidewalks of VeronaClick thumbnail to view full-size
Verona Quarries: Where this Ammonitic Limestone Came From - An unexpected "discovery"
So, one day Jer and I decided that, instead of taking the bus into downtown Verona, we'd explore in the opposite direction from our B&B on the outskirts of the city. We grabbed our daypacks and started walking north into the countryside and the foothills of the Alps, with no particular plan.
Eventually, our wandering brought us to the beginning of an enticing footpath at the base of a steep hill. Up we went through the thick vegetation, switch-backing along the narrow, rocky trail. We were looking forward to the view at the top, wherever the top might be.
And what a view it was, with the snow-capped peaks of the Alps to the north and the fertile valley, filled with farms and clay tiled roofs leading towards Verona below us and to the south. Then there was the surprise a little further along and behind us: the opening to what we thought might be prehistoric caves.
Upon further inspection, we hypothesized that what had begun as prehistoric caves had been enlarged sometime around WWII as a hideout from the Nazis. Our imaginations were running wild.
We'd heard there were prehistoric caves somewhere in the area, so we thought that's what we'd found. But they'd definitely been enlarged, and we saw evidence of machinery in the texture of the walls, which you can see in one of the photos below.
The caves were so deep and and dark, we were afraid to venture too far in. So we did our hypothesizing and picture-taking from just inside the entrances. And there were many of them all along the side of the hill.
Later, back at the B&B, we asked our hostess about the caves. Her English was only slightly better than our Italian (meaning, we really couldn't communicate very well), so she fetched her husband, who managed to convey that those were actually old quarries, which supplied the city with limestone. Ammonitic limestone as it turns out. And those "caves," well, apparently they had never prehistoric dwellings or early- to mid-20th century hideouts.
Oh well, so much for our imaginations.
More Photos Inside, Outside, and From the Abandoned QuarryClick thumbnail to view full-size
Want to Learn More About Ammonites? Read this....
A comprehensive Wikipedia article including the characteristics, classes, life, distribution, diversity, and death of this group of invertebrates
© 2013 Deb Kingsbury