Whispers from Deep Time: My Quest for Dinosaur Eggs

 By Steven Wade Veatch

             Forget the colossal dinosaur skeletons, the giants of paleontology. For me, the real, heart-stopping treasures are fossilized dinosaur eggs. They're not just relics; they're delicate, astonishingly scarce snapshots of these prehistoric reptiles. Composed of fragile crystals, an eggshell is a miracle that survived eons of geological forces. This inherent fragility makes any find a momentous occasion, especially those shells from the Jurassic Period.

My journey in search of fossils led to the Morrison Formation, which crops out over a vast area in Colorado. Though famed for its giant sauropods, it unexpectedly coughed up a critical piece of the paleontological puzzle: at least six different spots containing both Jurassic eggshells and whole eggs, a true rarity for a time period between 155 to 148 million years ago. As one of the world’s premier Late Jurassic fossil sites, the Garden Park Fossil Area yielded the first discovered remains of iconic dinosaurs like Stegosaurus, Diplodocus, and Allosaurus. It famously served as a primary battleground for the 'Bone Wars,' the legendary 19th-century rivalry between paleontologists Othniel Charles Marsh and Edward Drinker Cope.

The local action centered in the Garden Park Fossil area of Fremont County, Colorado. The whole thing kicked off in 1991, when Kenneth Carpenter of the Denver Museum of Natural History found a well-preserved eggshell fragment while collecting fossil snails (Hirsh 1994). That initial find paved the way for more fragments and eventually led paleontologists to the site that became the focus of scientific inquiry: Egg Gulch (Figure 1.).

Figure 1. General location of Egg Gulch in Garden Park, north and west of Cañon City, Colorado. 

At Egg Gulch, weathering and relentless erosion had stripped away layers of rock, revealing ancient eggshell fragments scattered across a rugged, 10-meter slope (Figure 2.). The presence of tiny fossilized freshwater plants called charophytes established the site's age as early Kimmeridgian (157.3 to 152.1 million years ago), making it the oldest dinosaur eggshell site in North America (Alf, 1998).

Figure 2. Under a brilliant spring sky, the crack team of volunteers from the Dinosaur Depot and the author are in the field, exploring Egg Gulch and painstakingly unearthing rare Jurassic dinosaur eggshells. This 1998 trip followed several years after the discovery of the nest. The Bureau of Land Management protects this area. You can’t dig here or take anything without a permit. We had such a permit as the collection of these fragments was for scientific purposes. Photo date 1998 by S. W. Veatch.

The initial surface collection in the early 90s produced hundreds of shell pieces. But the biggest prize was the discovery of an embryonic dinosaur bone at Egg Gulch—proof that life and death had played out right here (Alf, 1998). An entire nest of eggs was collected there (Figure 3).

Figure 3. Dinosaur egg clutch from Garden Park, Colorado. Now on exhibit at the Denver Museum of Nature and Science.  Photo date 1997 by S. W. Veatch.

In 1989, after the dinosaur nest with eggs was found, I was part of a field party from Cañon City’s Dinosaur Depot (Figure 2.). We wanted to see if we could find something new. It was time to get serious. I felt the true weight of that when I visited Egg Gulch.

We couldn't just aimlessly wander; we implemented a systematic approach to finding eggshells by spreading out and working our way up the slope, much like a TV search party looking for evidence at a crime scene. The fragments were larger and more concentrated closer to their source. Each shell fragment was bottled and meticulously labeled. I noticed the fragments were mostly concentrated on the flat areas and small ravines, washed out during intermittent rainstorms.

I remember finding my first piece of eggshell. I froze, the heat of the summer day instantly forgotten, my breath catching in my throat as I peered into the deep, spiky shadow cast by a cactus. My heart hammered a prehistoric rhythm against my ribs. There, nestled right against the face of a sandstone outcrop, was not just another bleached pebble, but something impossibly rare and ancient: a tiny, curved shard of a shell. Its color resembled that of a black crow’s wing mixed with desert dust, while its faintly bumpy texture hinted at something hidden beneath. With trembling fingers, I carefully plucked the Jurassic dinosaur eggshell fragment from its hiding place, feeling a silent, electric surge connecting me to a world ruled by thunderous giants, a treasure that had patiently waited, buried under the silent sun, for 150 million years.

Back in the lab, the shells underwent rigorous microscopic analysis. Radial thin sections, viewed under polarized light, showed the internal architecture, and highlighted that most fragments were heavily eroded. Lab technicians also used a technique called cathodoluminescence (CL), which causes the material to emit light when exposed to an electron beam (Alf, 1998; Boggs, & Krinsley, 2006; Götze, 2012; Götze, Plötze, & Habermann, 2001; Marshall, 1988; Pagel, Barbin, Blanc, & Ohnenstatter, 2000). This showed that the original shell material in some fragments had been replaced by silica.

Figure 4. Microscopic cross-section of a Jurassic dinosaur eggshell recovered at the Egg Gulch locality. According to Alf (1998) laboratory analysis revealed extensive recrystallization and diagenetic alteration in several shell samples. Siliceous replacement likely occurred as a result of the decomposition of the shells' organic matter. Photo courtesy of the Dinosaur Depot. 

Because it is not known which species laid the eggs, paleontologists use an artificial classification system called parataxonomy. The most common eggshell type was assigned to the family Prismatoolithidae, and named Prismatoolithus coloradensis (Hirsch,1994).  I also found a second, rarer, very thin dinosaur eggshell that was too altered to classify.

Remarkably, the Egg Gulch shell structure is similar to the Orodromeus eggshell from Cretaceous sites. Orodromeus was an ornithopod (bird-hipped) dinosaur. In the Garden Park area, the only known ornithopods are Dryosaurus and Othnelia. All the evidence points to one of these two as the likely parent of the P. coloradensis eggs.

 

Figure 5. Discovering Jurassic age dinosaur eggshell fragments right on the surface of the Morrison Formation is incredibly exciting because these delicate, ancient remnants offer a rare, tangible link to the reproductive lives of the prehistoric reptiles that once roamed this landscape. It's a thrill to realize that just by walking across these rocks, you're picking up direct evidence of where a dinosaur mother may have nested over 150 million years ago. Photo date 2023 by S. W. Veatch.

Collecting these rare Jurassic dinosaur eggshells marked a highlight of my summer’s fieldwork. The dinosaur eggshells unlocked a story of multiple nesting seasons and preservation, all providing invaluable data on a globally scarce fossil resource. The resulting story provides a tangible connection to life 150 million years ago, a whisper from the past made loud by patient, detailed science.

 

Figure 6. Nodular patterns or ornamentation, as seen in this image, is primarily hypothesized to have served in functions like shell strengthening, and may have also been related to respiratory gas exchange through specialized pore arrangements. Photo date 2023 by S. W. Veatch.

Acknowledgments:

            Some of the information presented in this report was gained from a number of field trips undertaken by the author to the Garden Park Fossil Area and from former Dinosaur Depot personnel Donna Engard, curator, and Phil Wilder, program coordinator. The author is grateful to Bob Carnein for his thoughtful suggestions and insightful review of an earlier version of this manuscript, which led to significant improvements. Special thanks are also due to Sawyer Blizard for creating the accompanying map and for sharing valuable time on-site examining and discussing Jurassic age dinosaur eggshells.

References and further reading:

Alf, K, 1998. Preliminary study of an eggshell site in the Morrison Formation of Colorado: Modern Geology, Vol. 23, Part 2., pp 241-248.

Boggs, S., Jr., & Krinsley, D. H. 2006. Application of cathodoluminescence imaging to the study of sedimentary rocks. Cambridge University Press.

Carpenter, K., pers. comm.: Department of Earth Sciences, Denver Museum of Natural History, March 17, 1999, (telephone interview).

Götze, J., Plötze, M., & Habermann, D., 2001. Origin, spectral characteristics and practical applications of the cathodoluminescence (CL) of quartz — a review. Mineralogy and Petrology, 71(3-4), 225–250.

Götze, J. 2012. Application of cathodoluminescence microscopy and spectroscopy in geosciences. Microscopy and Microanalysis, 18(6), 1270–1284. 

Hirsch, K.F., 1994. Eggshells from the Western Interior of North America.  In Carpenter, K., K.F. Hirsch, and J.R. Horner, eds, 1994, Dinosaur Eggs and Babies:  New York:  Cambridge University Press, pp. 137 – 150.

Marshall, D. J., 1988. Cathodoluminescence of geological materials. Unwin Hyman.

Pagel, M., Barbin, V., Blanc, P., & Ohnenstatter, D. (Eds.). 2000. Cathodoluminescence in geosciences. Springer-Verlag.

Unearthing Ancient Fossils: A Reflection on the Giants in My Life

By Steven Wade Veatch

I remember a scorching summer afternoon in 1992, when, with my new wife Shelly and mother-in-law Karen, I walked on a trail that meandered down the hill known as Cope’s Nipple—named after the 19th-century paleontologist who explored this site for dinosaur bones. People refer to the area as Garden Park, and it is located a few miles north of Cañon City, Colorado. 

With my mother-in-law in tow, I took the lead and attempted to be on my best behavior. She was visiting us from Interlochen, Michigan. As we walked, her presence loomed over me, casting a shadow that seemed to stretch endlessly. The air was heavy with her silent intensity, making the surroundings feel eerily quiet. I imagined a pleasing scent in the air. It reminded me of my mother-in-law's garden in Michigan. This added a mysterious touch to the atmosphere. It felt as if every step we took was heavy, as if her presence alone had a gravitational pull. My thoughts went back and forth between making a good impression on her and conjuring in my mind—since we were walking on a dinosaur graveyard—a spike-tailed Stegosaurus defending himself from an Allosaurus.

Depiction of an Allosaurs prowling about in Garden Park
during the Jurassic Period. AI generated image.

As I walked through this area, memories flooded back from two years before when I had explored it with a friend. As we made our way up a hill on that sunny day my friend and I unexpectedly came across a hilltop ornamented with an abundance of petrified wood. The sight was mesmerizing, with the hill covered in these ancient, hardened remains of trees. The wood appeared as if frozen in time, its intricate patterns and textures on full display. The crisp sound of our footsteps echoed through the stillness of the hilltop, adding an eerie ambiance to the scene. A faint scent of earthiness lingered in the air, reminding us of the long history embedded in these petrified remains. As we gently touched the wood, a cool, smooth sensation greeted our fingertips, connecting us to the past. We were the first ones to see all of this petrified wood. If someone had been there before us, all the wood would probably have been taken.

Shelly and Karen kept up with me as we continued to descend Cope’s Nipple. The scorching sun baked everything in a relentless heat. While we were going down a gentle slope, Shelly and Karen talked about how different this landscape was than the woodlands and humid air of northern Michigan. Shelly vividly recounted to her mother the harrowing encounter she had had a year before, when a venomous rattlesnake unexpectedly lunged at her on an earlier trip here. She urged her mother to remain vigilant and attentive while going down the pathway.

It was the hottest part of the day as we continued to walk along the trail that now cut through a dark-red disintegrated siltstone, part of the world-famous Jurassic-age Morrison Formation. Insects buzzed under an intense Colorado blue sky. A scorpion scurried with a quick dart beneath a cracked slab of siltstone, its jagged edges leaning against a smooth cobble of quartz. Time seemed to slow down in the heat, and seconds lingered in the dry air. 

I had been here in the spring of 1991 with a prospector buddy. On that day, while ascending a ravine, we stumbled upon huge heaps of bentonite clay. It had rained the night before, and the clay had swollen up to five times its normal size. Nodules of a lilac-purple St. Stephen’s agate were bulging out of the swollen, wet clay. I crawled up the side of a clay mound and plucked out one of these agates. As I held it to the sunlight to see the concentric layers inside, I slipped and slid down the slick clay on my backside. Wet, cement-like clay covered my back to my head. There was no way to wash it off, and it was solidifying in the arid air. My wife had a lot to say about this when I returned home. She also wanted to see this place, Garden Park, the next time I went.

Now my adventure with my wife and mother-in-law heated up. The dirt-covered path, lined by piñon pine, was in the middle of a dinosaur graveyard and was under the protection of the Bureau of Land Management—no fossil collecting allowed. I couldn’t imagine dinosaurs once ruled this dry, semi-arid land covered with yucca and cactus. As we walked along the trail Shelly’s voice poked into my consciousness. She had just bent down to pick something up from the side of the path. She was describing it to her mother: “It’s cone-shaped with a subtle curve. It has a pointed end.” She continued, “The other part of this is not pointed. There is a serrated edge.” The word SERRATED thundered across my consciousness. I asked her if I could see it. She handed it to me. I knew at once she had stumbled upon an extraordinary find—a pristine Allosaurus tooth, a relic from a formidable dinosaur that once reigned supreme in Garden Park’s prehistoric ecosystem. The ancient fossil, with its sharp edges and intricate ridges, exuded a sense of raw power. As I held it in my hand, I could feel the weight of its history, imagining the ferocious battles it had fought. The sight of the tooth gleaming in the sunlight transported all of us back to a time when mighty dinosaurs roamed the land. The faint scent of earth and ancient fossils lingered in the air, arousing a sense of awe and excitement. 

It was now time to finish the hike. We left the hotter, drier landscape for a riparian environment. Four Mile Creek greeted us as it sliced its way through a scenic valley adorned with cascading layers of limestone, siltstone, and sandstone. The gentle sound of flowing water filled the air, harmonizing with the rustling of cottonwood leaves along the creek bank. The earthy scent of wet soil along the stream mingled with the refreshing aroma of the nearby vegetation. As we stood there, we couldn’t help but feel a sense of awe and wonder at the natural beauty surrounding us. 

The day changed, it shifted into something new. Shelly’ discovery was important. You don’t find an Allosaurus tooth every day. My mother-in-law had a breakthrough in how she thought about me. She enjoyed our day together and listening to me talking about a vanished ecosystem filled with dinosaurs.

And I discovered how fortunate I was to have these two women in my life.