This was the last of our spring trilobite collecting trips for this year. We headed out to the House Range of west-central Utah (west of the town of Delta), long known to be a trilobite collecting mecca of sorts. I had never visited this area before, but had long heard rumors that trilobites there are so common you could just pick them up off the ground. These are the common types of trilobites (usually Elrathia kingi) that you will see in nearly every rock shop across the United States. John was interested in visiting to gather some more data for his presentation at the International Conference on the Cambrian Explosion.
The trilobites we collected were from the Middle (to Late?) Cambrian Wheeler Shale, Marjum and Weeks Formations. Lucky for us we had a friend along who was familiar with the area and could show us some good collection localities. But it is not hard to see where others have looked. As you drive into the area it is pockmarked with hundreds of holes. It is kind of sad (to me) to see the area just destroyed all in the name of looking for trilobites. There are really no regulations it seems to keep people from doing this. The land in this area is mostly BLM land, and it is legal to collect a reasonable amount of common invertebrate fossils. But this is where the trouble starts. It appears that many people in the area operate "Flagstone quarries." The one I visited had already been shut down by the BLM, but sadly these people left a HUGE hole in the ground, large amounts of trash, and nearly a hundred banded up, ready to go, pallets of rock.
When you look closely at the rock, this is what you see:
Those are hundreds of inarticulate brachiopods (Acrothele?). I would guess they classify as a "common invertebrate fossil." But the BLM website clearly states "If you wish to collect common invertebrate or plant fossils for landscaping, sale, or commercial purposes you must apply to the BLM for a mineral materials sale." [link] I guess these people had not done that, or were being deceptive and selling trilobites. Who knows?! We observed trilobites in these pallets of rocks. The trilobites at this site however would typically require some sort of preparation (air abrasion).
It was cold and windy most of the time we were there, which was not a blast, but at least it was not raining or snowing. The last day was great - sunny and warm. We took the dog again and he seemed to have fun.
The shales were pretty easy to split. The limestones required a little more muscle, but were nice to work with. We found more complete trilobites here than we did in either the Marble Mountains or at Spence Gulch, but they are often missing their cheeks.
There were also some pretty big trilobites out there (larger than at any of the other sites we have collected at):
We also spend a morning looking for eocrinoids (Gogia). We found two.
There were also commercial collecting spots located in this area where you can actually pay these people to dig up rock with a back hoe and give it to you to sort though, so you can find your own trilobites. Seems barbaric and like cheating to me, but that is just my opinion. Why in the world would you pay people to do this for you when all you have to do is get out of your car, walk 100 yards and look down. Seriously, it was that easy in most areas. Looks for some shale and then look down. I guess if you did not know what you were really looking for, but it seems like a waste of money to me. In the first picture below you can see the number of trilobites we surface picked at one site.
Some other fun trilobite pictures from the trip:
© ReBecca K. Hunt-Foster. Please see the "Field Work Friday Rules" about the work I do and collection practicies.