Shamalama Summer Vacation Day 4 & 5

[Shamalama]

Day Four - September 2nd, 2009

Today was fairly uneventful. I’d decided to try and prospect some sites in the Confusion Range for fossils from the Permian and Triassic periods so I headed towards Cowboy Pass as my first destination. My route took me through the Wheeler and Marjum formations of the House Range and I saw all the prospects into the Cambrian aged rocks looking for Trilobites. I figured I would do some of that tomorrow and mentally marked the areas to visit. After getting through the Marjum Pass I crossed Tule valley which is a flat expanse broken only by a small series of hills. I recalled that I was in the Basin and Range province of North America and this was a perfect example of the geologic phenomena. This region of the continent has experienced stretching and so the crust forms horsts and grabens. A Horst is an upthrust block of crust while a Graben (German for ditch) in a downthrust block. They often occur side by side separated by faults. In this case, the House and Confusion ranges could be considered Horsts while Tule Valley is a Graben. I made my way across the valley and into the Confusion Range (so named because of the early confusion surrounding it’s geology). Following my research I drove to a point in the mountains where a formation of Triassic age rocks should be. I spent about a hour hiking up and down some small hills looking for any evidence of fossils and finding very little. I found one layer with what seemed to be small clams but they were so badly weathered that it was practically worthless to me.

View of the Confusion Range

Since the mountains were living up to their name I decided to head back to the House Range and look for some Trilobites. Coming back through the Marjum Pass I spotted a small hill with some diggings on it and decided to take a look. The base of the hill was Wheeler Shale, a very thin bedded limy shale that splits easily, while the top was limestone of the Marjum formation. Starting at the base of the hill I inspected every piece of rock looking for evidence of Trilobites. I found quite a few pieces of shale that either weathered out or were discarded by others with fragments of Trilobites on them. I was even lucky enough to find one piece with what looks like a Trilobite in a partially enrolled position. I continued to climb the hill and found more Trilobite fragments and some odd looking pieces of shale with what looked like either trace fossils or possibly algae or sponges on them. As I got towards the top of the hill I started to find more talus from the Marjum formation and was excited to find black Brachiopod fossils preserved in the orange weathering limestone. Continued searching turned up some more fragments of Trilobites and another whole one.

View of the hill

A prospect

Findings

Brachiopod

Trilobite

Happy with my finds I descended the hill to move onto another area. I drove up the road a bit until I saw some more shale covered hills and pulled off. Searching these areas I found lots of little Agnostid Trilobites but not many others. Some were colored black and others red but they were common enough that I gathered many samples.

Agnostid Trilobite

My final stop was a short distance up Amasa Valley where it’s possible to get access to the Weeks Limestone. I was hoping to maybe find some rare or unusual Trilobites but the prospect I choose seemed to be barren of any good fossils. I drove a little further past the first prospect and found another quarry where apparently they thought they might mine a large seam of white Calcite. It looks likes it was a travertine deposit at one time because you could see the obvious layering and growth patterns that looked like either cave or hot spring formations. There were some interesting pieces but I decided that none were worth me having to ship home.

I knew that I could find some interesting minerals if I drove farther up the valley but by this time it was getting late and I decided to head back to Delta and visit the two rock shops in town instead. The first place I stopped was at West Desert Rock Art. When you walk in you’ll likely be greeted by the owner’s boxer Scooby. She is very friendly and generally just wants a little attention before she goes back to flopping out on the floor. I looked around at what they have available and they have a decent selection of typical rock shop touristy stuff as well as some lapidary rough, fossils and mineral specimens. Initially not impressed, my eyes fell upon their book rack and I started to drool. There were several good tomes of information on sale and I choose a copy of “Rock, Mineral and Fossil Sites of Utah” which was published by the State Geological survey a number of years back before liability issues and site popularity forced them to pretty much curtail publishing any collecting sites. Some of the info is spotty but can be a very good resource when prospecting for sites. I am kicking myself right now as I type this that I didn’t get a copy of the “Geology of Millard County” while I was at the shop. Well, maybe I can order it from them later. One of the people manning the store (I remember just about everyone else’s name but his, sorry) asked me if I needed any help and we got into a conversation about the Trilobites of the Wheeler shale. He invited me back to where they do their prep/storage and introduced me to Robert Harris (his name I remember!). He showed me some of the Trilobites they had found and pointed out some very nice red Trilobites. I thought all Trilobites from the Wheeler Shale were black but apparently some are Red! Bob then proceed to tell me about the quarry where some can be found and drew me a map of the area south of the U-dig quarry. He was also kind enough to give me pointers on where else to look (away from the sites everyone visits) and gave me written permission to go into his quarry which was next to U-Dig. We talked some more and I showed them the couple of Trilobites I’d found including the one from the Marjum limestone which they thought was neat. They then showed me a case with some of their prize and rare Trilobites they’d found (!) while digging. It pays to be a local as you get to hit a layer or site as often as you want and will have a better chance at finding the rare stuff. I wound up adding a nice 1.25” red Asaphiscis in matrix, five 1.5” popouts (two Elrathia and three Asaphiscis) as well as a repaired Gogia Spiralis and shop t-shirt to my bill before I left.

Red Asaphiscis

Large Popouts

I was very happy with what I’d seen at their shop and the info that Bob had given me so I headed off to “The Bug House” which is the other shop in town. The Bug House is run by the same family that operates the U-Dig quarry and is responsible for keeping the Dugway geode site productive. They have a couple of sheds next to their house that they use for storage and their business. I walked into the store and the front is very small, maybe 15'x10’, and has lots of generic rock shop stuff that kids and tourists would like. I saw a few Septarian nodule products that they make on premises and some Dugway geodes but not much else that caught my eye. It turns out they are getting things packed and ready to haul to the Denver Mineral and Fossil show which begins the weekend after I leave town. I did buy a Septarian slab, four Septarian eggs and a small cut and polished Dugway geode that caught my eye before I left and they gave me a real bargain on them! I guess since they mine and cut/polish their own stuff they can afford to be generous on pricing….. or maybe it was my good looks. Nah… the former is probably true. Before I left I took a picture of a whopper of an egg they had sitting in their shop. It was a huge Dugway geode that they had cut and polished into a large egg shape that was 18” tall, 18” around and with a beautiful crystal interior of while Quartz. It’s truly a massive specimen and the shopkeep told me that the person who polished it hurt their arm pretty badly trying to keep it up to the polishing machine. I imagine that it weighed a good 100 lbs. easily. Exhausted from the day I returned to my hotel and hit the sack like a ton of bricks!

Geode Egg

[Shamalama]

Day Five - September 3rd, 2009

After talking with Bob Harris the day before I headed straight for the “Red Quarry” which he’d described to me. A few bumpy miles later I saw a freshly graded road running beneath some power lines. I’d seen a number of similar roads in the last few days and it wasn’t until I had about destroyed the shocks and struts of the vehicle I was driving that I finally figured out they had been made to allow work crews access to the lines for maintenance. I finally got off the rough graded maintenance road and onto the correct gravel road that Bob had told me about and was back on track. A couple of miles later I see some prospects along the side of the road. I decided to check them out as some were into the red shale that Bob mentioned had red Trilobites. I did a little prying up of rock and didn’t find anything so decided to crack open some leftover rock that others had tossed aside. I managed to find a number of trilobites that way, though none were very large.

The Prospects

My Finds

After a hour or two of playing in the dirt and discard piles I got back on the road and drove a mere 1000’ before I saw the quarry I was looking for. It was hiding behind a hill which hid it from the prospects I’d seen. I wasted no time once I parked and was climbing the piles of rock which lined the entrance to the quarry.

The Quarry

I saw evidence of some large Elrathia and Asaphiscis but most of the rock was in huge chunks and was very hard to split. I looked in another part of the quarry and found some tan-red rock and started to see quite a bit of Trilobite material so I settled down to splitting. I found about half a dozen decent trilobites that were red instead of the usual black. I’m not sure what caused the color change but it was a pleasant difference. I’d spent a hour there and still was not finding anything big so decided to head to U-Dig and see if I had better luck. I wanted to see the quarry and see how the experience differed from when prospecting on my own.

Reddish Trilobite from the quarry

I pulled into the quarry and paid for a two hour ($28 for two hours, $70 for full day) visit. For those who might think that is pricy, and in the interest of neutrality, there is another quarry just above U-Dig called “A New Dig” that charges $20 for two hours and $60 for a full day. The owners of U-dig have pretty much carved the edges off a large hill with the center part standing like an apple core. There are huge piles of the shaley limestone everywhere and some places you can dig out your own rock from the walls. The person who was on duty (I forget his name) told me they’d dug a test pit just over the debris pile and that they’d found some good stuff there, so I headed past a small group from Virginia to the area he’d described. It really was just a test pit which consisted of not much more than a scoop or two of the track hoe into the earth and exposing two to three feet of shale. I puttered around on the nearby dump piles and found a few large (3/4”) “pop-outs” of Elrathia missing their free cheeks and a number of incomplete large (3/4” – 1”) Asaphiscis. “Popouts” are when the Trilobite fossil pops off the rock matrix intact on both sides. Where the test pit is located is right next to the bottom of the tailings piles. So I walked along the base cracking many large rocks hoping that they had been weathered a little more and would break more easily. The rock is a limy shale but sometimes likes to split in shards or splinters when fresh. I had a lot of luck at the base of the piles where I found four complete Asaphiscis that were ¾” or larger. By now it was getting to the end of my two hours and I was getting tired. It was over 90 degrees out and that can wear a person out despite the fact that the humidity was maybe 15%. I climbed back up the 30’ tall dump piles with my finds back to the hut where you pay your fee. Wheezing (remember, I live near sea level) I plunked my rocks down to show the guy my finds. He took a dremel tool with a stainless steel brush and started to clean/polish some of the trilobites on the rocks and then remarked that I’d found three juvenile Asaphiscis which is fairly unusual. Apparently they are generally found in sizes 1” or larger and the smallest I had was ¾” long with the other two being just under an inch each. I guess Asaphiscis shells are delicate and so don’t always preserve well when younger. Tired but happy, I guzzled a 32oz bottle of Gatorade and hopped back into my car for the ride to Green River and my hotel room for the night. I guess I could have spent an hour or so searching through Bob Harris’ quarry next door since he gave me permission but I was really tired and getting sunburned plus I had a long drive ahead of me. I forced myself to drive past the West Desert Rock Art shop so that I didn’t spend any more money because tomorrow I would be visiting Capitol Reef National park to change things up a bit.

3/4" Juvenile Asaphicis next to a popped out Elrathia

Popouts from the piles (largest is a little over 1"

[tracer]

interesting stories. i particularly like when narratives and pictures of field trips are posted like this. i get to go somewhere without leaving my house.

[Terry Dactyll]

Dave.... The red trilo looks really crisp quality... well done.....

[Guest solius symbiosus]

Well said tracer! Narratives accompanying hunting reports make for some fascinating reading... a virtual field trip.

Now, how about some more of that tensional stuff for us folks back east.

[tracer]

wait! what's "tensional stuff" mean?

notice how i'm not afraid to sound stupid?

[Kentuckiana Mike]

Another great set of detailed field trip reports!

It would be nice to find intact trilobites like that in the Ohio River Valley.

I am glad you found such good specimens.

Good luck on your future collecting expeditions.