Rockhounding Union Wash for Fossils

A Rolling Rockhound Review

Ammonite aka ammonoids found rockhouding in Union wash, Inyo County near Lone Pine, CA
Ammonite in black limestone

Triassic Period Ammonite and Tube Coral

After doing a little bit of research and collecting GPS coordinates to get us close, we took a drive to Union Wash to do some serious rockhounding for Fossils. Union Wash is well known for its limestone deposits of fossils, specifically Ammonoids.

What are Ammonoids anyway?

What are Ammonoids you ask? Ammonoids, also called Ammonites are a spiral-shelled sea creature with squidlike tentacles that lived during the Devonian Period (419 million years ago) to the Cretaceous Period (66 million years ago). According to Brittanica, they are “related to the modern pearly nautilus…” The type found at Union Wash are of a structure that places them in the Triassic Period ( 252 – 201 million years ago). Ammonite fossils are used as index fossils, meaning that enough is known about them to date other fossils found in their vicinity.

Wait a minute! Did I say Triassic?! 252-201 million years ago?! Man, oh man, does that put life in perspective! And wait… SEA creatures? but, I’m in the desert. Now see, Geology can be kinda cool! I hope to share bits and pieces in future blog posts. It is quite a bit in one big mouthful, sorta mind-blowing, so we’ll just take it in snacks and appetizers.

Okay, on to the search!

Getting There…

Beware – it’s a ROCKY drive! Take it slow. It is also on the border of the Inyo Mountain Wilderness. Wilderness areas have more regulations than BLM or Forest Service lands such as no digging and no motorized vehicles. Please make yourself aware of the boundary and the regulations. Gaia Maps has some great overlay options and both BLM and the NFS are only a call away (numbers provided below).

Union wash rockhounding for fossils, ammonites in limestone deposits. cactus and Inyo Mountain Wilderness
Union Wash and the Inyo Mountains

This area is rich in mining history and many minerals have been found in the general area. However, on this day I was intent on finding fossils! I can’t wait to get back and just do some more rockhounding, hiking, and exploring.

Road into union wash rockhounding site, fossils, ammonite
Upper Union Wash

The drive from downtown Lone Pine is 10 miles. Drive US 395 North from the center of Lone Pine and make a right turn (east) on Pine Narrow Gauge Rd. Drive 3.4 miles to Owenyo Lone Pine Rd. Lone Pine Narrow Gauge Rd turns into Owenyo, where you will turn left (north) onto Owenyo Lone Pine Rd. Drive 4.6 miles and then turn right onto a dirt road. Take the dirt road about 1.5 – 2 miles up. It’s a slow rocky drive. Park and hike up to the ridge on the southern side of upper Union Wash. As an alternative, you can use the Google Maps link below to get directions to Union Wash.

Finding the little buggers!

We parked where we estimated the wilderness boundary to be and hiked in. I carefully made my way up the wash, climbing up and down slippery slopes of black limestone scree on the north-facing slope on the south side of the wash. After hours of fruitless slippery searching, I decided to hike back to where we’d parked the truck. Walking the “Rockhounder’s Wedding March” (as I call it), one step forward, stop and look, step the other foot forward, stop and look. And lo and behold, just a mere few hundred feet from the truck, I found Ammonites in piles of limestone scree at the base of the slope and in the wash.

Collage of ammonites found at Union Wash, California near Lone PIne CA
Ammonites in black limestone from Union Wash
Tube Coral found in Union Wash rockhounding for fossils, california, inyo county
Tube Coral found at Union Wash

I was also fortunate enough to find a very nice specimen of tube coral.

By the time I had reached the truck, the family was hot, tired, and out of water. Even though I was energized by my finds it was time to call it a day.

If you take a trip to Union Wash – please let me know what you find! Remember that only surface collecting, freely eroded, loose fossil specimens may be kept in the Inyo Mountain Wilderness which is under the joint jurisdiction of BLM and NFS.


I am not an expert! I’ll do the research and reconnaissance and share with you what I discover, but it’s always a good idea to do your own research before heading out into the field.

  • Site: Union Wash near Lone Pine, California on the eastern side of the Owens Valley
  • GPS: 36.7066, -118.0361 to the general area
  • Gem, Minerals, and/or Fossils possible: Ammonoids/Ammonites
  • Gem Minerals and/or Fossils found: Ammonoid and Tube Coral Fossils
  • Surface, dig, other: Surface Collection only! Surface collecting only! Only freely eroded, loose fossil specimens can be collected.
  • Public lands jurisdiction or private ownership:

My personal GO To’s

Below are some items that I have found useful. The image for each product is an Amazon Affiliate link. That means that, at no cost to you, I will earn an affiliate commission if you click through the link and finalize a purchase. I only recommend products that I believe in.


Most of my guides are Kindle versions because as a full time RV’r I have little room for all the guides and books I’d like to have. Many times I wish I had the paperback version instead to make notes and more easily have in hand. Although, with the Kindle version, I can have a copy available on either my iPhone Kindle App or my actual Kindle. So, in some cases, I have both!

Safety Device

Okay! This is a serious subject for me. I think everyone should have a satellite tracking device for emergencies. There are just too many stories about people being saved because they had one.

My Partner, Mr. RR and I each have one. We each have one for two reasons.

  • Number One Reason is for an emergency. Say one of us becomes indisposed, falls off a cliff with the device or we become separated.
  • Number Two Reason is that the inReach Explorer has satellite texting capability meaning that we can communicate with one another in remote areas in which our cell phones do not have service. (The others may have this ability as well but we have the inReach Explorer so that is the one that I am most familiar with. We have been using them for several years now and “wouldn’t leave home without them”.

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