Antelope Spring, Utah
My first encounter with the trilobites of Antelope Spring was some two-and-a-half decades ago. We were living in Michigan at the time,
and my parents, sister and I took a trip "out west" to see what there was to see. When we reached Utah, we headed south toward
the basin and range country around Delta, because my mom had a sketchy description from a fossil guidebook indicating that
trilobites could be found there. We headed west out of Delta on US 6-50 and took a turn to the right on an unmarked gravel road (not
much more than a cowpath) snaking north through the Whirlwind Valley and into the House Range. Just about the time we thought
we were lost, we encountered two guys in a truck who worked for the BLM. We stopped to chat, and one of them asked if we
had anything for a headache. Those of you who know me know that headaches are my "Achilles' heel," and I always carry some kind
of medication with me. We were glad to help him out. When they found out we were looking for trilobites, they said, of course,
just continue up this road a couple more miles and into the hills. When you see the spring on the left, stop and start hunting.
We couldn't have imagined beforehand how prolific that hunting would be. We had barely parked the car when I found the
first trilobite, a broken Elrathia kingi embedded in the dark grey rock of the middle Cambrian Wheeler Shale. Even though it was
a pretty poor specimen, I was ecstatic. Little did I know of the riches to come. In those days the whole area was pretty deserted,
and you could roam the ridges and valleys to your heart's content. Where the arroyos were scoured clean, you found mostly
impressions of trilobites in dark shale slabs. The slopes consisted of lighter material, weathered to clay, which produced whole black
trilobites free of matrix. Most were
Elrathia, ranging from practically microscopic to about an inch long. Many were missing the
free cheeks, evidence of their having once been molts, rather than the remains of trilobites that had died. The ones with a bigger
glabella were Asaphiscus wheeleri. I quickly came to prefer the "free" trilobites over those embedded in the heavy, sharp slabs of matrix.
Small inarticulate brachiopods sometimes were also found in the shale slabs, but were too delicate to weather free. Much
less common than Elrathia and
Asaphiscus were the little agnostids or "double-headed" trilobites. I think I only found three or four
of them in the several days we were there, compared with bags and boxes full of the others.
The following year, I took Chris back there on our honeymoon. He didn't know much about fossils, but liked camping in the
middle of nowhere. Some nights we camped near the trilobite beds, and when we wanted a bath, drove back to Delta and north about
20 miles to the Little Sahara Recreation Area, which has a nice campground with water at the foot of gigantic sand dunes. The noise
of ATV's is disturbing during the day, but most days we were back at Antelope Spring hunting trilobites. The hills around the
trilobite beds are covered in a sparse piñon-juniper forest, and the valley opens out to display a wonderful view of the Sevier (usually)
Dry Lake in the valley to the southeast. More and more trilobites were added to my growing collection. They are so
beautifully preserved that it is hard to pass one up, even if you already have hundreds like it. And there is always the allure of searching
for "the big one". I did find an
Asaphiscus on that trip that was nearly two inches in length, the biggest one I have ever found. After
I returned home to my job at the GM Proving Grounds, I displayed some of the fossils I'd found on my desk for my co-workers
to inspect. I remember Larry asking me how old they were, and I casually answered, "Oh, about 500 million years." He asked,
didn't I mean 500 years? I was appalled to discover that he thought that fossils were formed when an animal died lying against a rock
and was absorbed. How could an educated person (albeit an engineer) be so ignorant of the planet around him? I thought, but of
course I didn't say it, and only explained in a few sentences how fossils were really formed.
By the time we returned in 1983, we had moved to Colorado and it wasn't such a long drive (for us; my visiting parents still
came from Michigan). The flooding Utah had experienced that year had filled the Sevier Lake. We walked across the salt flats down
to the water's edge, and discovered that hundreds of fish had been washed downstream with the flood waters and killed by the
salt water of the lake, littering the shoreline. Fortunately, because of all the salt, they didn't smell. By that year, we had our
dog, Rooter, and my parents had their dog, Tilly. The dogs loved roaming the hills as much as we did, although they were
more interested in sniffing cow pies than hunting trilobites.
Thirteen years and two childbirths passed before I was able to visit Antelope Spring again. I returned with my family in 1996 as
a field trip leader for the Western Interior Paleontological
Society. Things sure have changed. Gone are the days when the
trilobite digs are obscure and in the middle of nowhere. Sure, you still have to drive 40 miles from civilization on gravel roads, but they
are graded now and marked with signs. A couple of guys in our party even made it in a motorhome. Years ago there used to be
only one commercial quarry (the area is a mosaic of state and BLM land, and the "mineral rights" to the state parcels can be leased); now it is just about all leased, and posted with "no trespassing" signs. The biggest of the
commercial operations is called "U-Dig Fossils", which charges you by the hour to look for trilobites in a huge quarry excavated by
heavy equipment. The nice thing about U-Dig is that they have posted big signs at every road junction directing you to the quarry, so
you no longer have to worry about getting lost.
So, whereas the site is more accessible than it used to be, the trilobites are less. There is still a lot of BLM land in the area that
you can still roam freely on, though. I have heard that other types of trilobites can be found in the younger sediments atop Marjum
Pass, but I've never stopped to look. Maybe next time.
