Collecting Lower Cambrian Trilobites In The Mojave Desert

[trilobiteruss]

I had the good fortune after Tucson to spend much of the week with our good friend George Ast at Barstow, collecting lower Cambrian Latham Shale and Equivalents in the Marble Mts and Emigrant Pass (Nopah Range) in the Moave Desert. I thought a few photos (122 plus our of nearly 1000) and a log would be enjoyed by some of you so I share it in that manner.

Traveling thru the Mojave Desert of Southern California after leaving Nevada on I-15 on way to Barstow. Some views along way — passing Baker - where road to Death Valley is and where we will be going up near later in week on visit to Emigrant Pass in the Nopah Range.

Barstow at last. George is day behind us coming from Tucson. I spend night in motel in Barstow and Joe and Mike go visit Joes sun in San Diego 2 hours SW.

some views from Motel to the NE into the mts of the Mojave Desert basin and ranges.

sunrise to east from Motel in Barstow.

looking east towards the mts in Mojave where we are heading first day of Marble Mts collection in the Latham Shale (lower Cambrian)

Each of the two days we traveled out to the Marble Mountain site we traveled by a number of recent volcanoes and lava flows (common in the basin and range areas where the faulting and rifting brought magma to surface) these are all around 800-900 years old). One cinder cone and flow is seen in first picture on my gps and satellite map image on my smart phone as we drove by the flow and cone is clear as is the prevailing westerly wind flow from the cone leaving ash and such to the SE.

Next few images show the cone and flows of what I will call the Amboy cone as it is close to Amboy not far from the Marble Mts.

Last photo is another smartphone gps map image showing the cone closer for you view

We approach the southern Marble Mts and the Trilobite wilderness. You can collect here but you should have someone and or maps indicating where public lands (BLM) are. There are private areas and such so not all wilderness. I am aware of at least one area leased for the trilobites by a major well known collector/dealer. So just traveling into the Marbles without some help, a local or other friend who knows the area might be a bit more difficult.

views of the southern Marble Mountains along old route 66 called National Trails Highway just few miles south of I-40.

We are almost there for first day. Had to stop at the Cadiz sign. Not much of a town anymore. There is a Migrant Camp south of this sign as they have found good water at depth and they are now irrigating and growing crops nearby in the desert. From left to right: Joe Devera, me, and Mike Lewsader (all from Illinois — ISGS members, Joes Jems, ect).

George As tis taking pictures of us with the cameras on our phones (left to right Dennis Whitney - Missouri, George Ast - Barstow, Ca, and Geoff Thomas -Australia

we are at the southern tip of the Marble Mts.

approaching our collecting area.

we are here Lower Cambrian (rusty red top left/center is the Zabriskie Quartzite at base of section of interest, followed by the greenish to gray shales of the Latham (the target) and overlain by the Chambless Lmst. We will be collecting for first day up in the area with x marked.

A good view along strike from where we collected in Latham Shale day one. I have marked the Zabrinski Quartzite dipping to the right, followed by the Latham Shale that we collect, overlain by the Chambliss Limestone. Note a bit further out there is a repeated section of same rocks (out of site to right where we park there is more Zabriskie underlying this block, lots of fault blocks and repeated sections here which you would expect in the basin and range province that is the result of pull apart fault blocks (normal faults) and complex geology in same.I am standing on some Chambliss Lmst here taking picture.

Another annotated view to the north of our first day of collecting . Next day (day two in Marbles) will be collecting in the Latham in that Saddle of Latham Shale between the Zabriskie and Chambliss.

A large Bristolia bristolens George found. This is a good place to describe the trip. There were six of us experienced collectors. Each day amongst the 6 we only managed to find 2 complete lower Cambrian trilobites per day. Whole bugs are exceedingly rare, parts are not. George said he had probably been here 120 times or more and 90 of them came away with only parts. That is how hard it is to get the bugs.

Our group collecting in Latham Shale day one in Marble Mts, the saddle of more Latham along crop that I annotated in earlier images is seen here. Next day I will be collecting there. I have put in a simple “geology map” showing the outcrop of the Zabrinskie, Latham and Chambliss in this photo just to orient you to the spot and the steep dip of the Lower Cambrian strata.

Probably the most common trilobite part found are the numerous heads of Olenellus fremonti at the site. Some slabs are just covered with lots of them. This was one of the medium ones I found. I will insert in other images of some of the samples I took later in time.

Here is the complete 6 inch Olenellus fremonti Joe Devera found on day two just below where we were digging on day one and some dug on day two. I stuck this here since it was more appropriate to my discussion of this particular Olenellus we found at the site. He probably will be sending this in to be put back together like Dave Comfort does with this bugs, this gives you an idea of how they are found and when you see the complete bugs from here what kind of prep job is done to put the part and counterpart back together.

Views from on top of the Chambliss Limestone where we were collecting day one looking to the east to give you a flavor of the area and its stark beauty.

Ok ran out of space to upload this thread I guess on to another......

EDIT: Images removed by topic starter

[trilobiteruss]

Ok here are some more, probably will end up with serval posts I guess.

Back to the cars at end of day, looking back before we head back to Barstow for night.

Day Two scenery on way to Marble Mountains.

Along the old route 66 on way to the Marble Mts (south of I-40) this is another volcanic complex a bit to the west of the Amboy cone I showed you on day one. A large major cone to north of us in road that has blown out to the NW, and smaller cone to the south and east of road that blew out to the NE.

views of the smaller cone to south of road with its NE side blown out (again all this is 800 years old).

good view of our approach to the southern Marble Mts. They are the lower range you see first, the taller ones in background are different range.

approaching the Southern Marble Mts.

approaching southern tip of Marble Mts.

George talking to us about the southern tip of the Marble Mts and some sites there and interesting geologic notes.

I took a GPS/map location of where George was talking to us.

we are approaching our spot again in the southern Marble Mts

Geoff and I climbing the saddle you saw to north in Latham Shale from day one photos. You can see the trail on the slope of Latham Shale where we collected day one and some still collected including Joe who found the large 6 inch Olenellid I showed you above.

in area just below the saddle in Latham Shale looking east towards the outcrops of Chamliss Limestone.

climbing the Latham crop and strike towards the saddle where I spent day collecting with Dennis. Saddle is essentially the Latham Shale, Risistant rock dip slope on left is the Zabriskie Quartzite, and resistant cap on right of saddle is the Chambliss Limestone.

view on the Chambliss Limestone capping the Latham Shale Saddle. If you look in center above the Chambliss debris you can see our cars parked. Second photo you can see the trail to the first Latham collecting area.

View from the base of Chambliss on top of the Latham Shale saddle looking at the Latham crop above the Zabriskie dipslope where half of us collected again on day two

Algal Oncolites in the Chambliss Limestone

Two more views from top of the Cambliss Crop before end of day

Nice panoramic view from top of Chambliss at the saddle I was at all day. Shows the area we worked all week, and some of the geology.

Day 3 heading to the Nopah Range and Emigrant Pass to collect in lower Cambrian Latham equivalent (called Eagle Mountain Shale Member) and overlying equivalents to the limestone beds in upper Latham (called Thimble Ls Member) and Chambliss equivalents (Gold Ace Ls and Echo Shale Mambers)

On road to Baker and heading north towards the Nopahs….

on road to Baker GPS map

At Baker ready to head north to the Nopah Range.

Heading North out of Baker 712 (68) View Heading north out of Baker

further north out of Baker, view

Cool area of dunes resting against Mts north of Baker a bit on California 127.

Heading North on 127 past dunes, miles and miles ahead!

Ok that is it again for files.. dang it!!!!

Edited March 12, 2014 by trilobiteruss

[trilobiteruss]

Approaching Tecopah Hot Springs Park view and maps, and the junction of 127 with Old Spanish Trail Highway, ready to turn right)

looking at the Akali flats at Tecopah Hot Springs Park, and the Nopah Range (our destination in background).

On Old Spanish Trail Highway around south side of salt flats (white on map) and the Tecopah Hot Springs Park.

Nopah Range ahead!

end of alkaline flats beach Tecopah Springs, Nopah Range and Emigrant Pass ahead

Nopah Range Ahead. Emigrant Pass right above the car ahead in the break in the range.

Nopah Range, the brownish gray above the car is the Lower Cambrian target.

Lower part of the Nopah behind the sign is the Lower Cambrian equivalent to the interval we were in at the Marble Mts.

Emigrant Pass ahead.

stopping just above where car was in last photo looking to the south of the pass the base of the moutons and the saddle in distance between peaks on right and left are the lower Cambrian target we spent our day in. Peak on right is our old basal friend the Zabriskie Quartzite dipping to the left.

We were collecting in the Echo Shale-To Eagle Mt Shale Mbrs of the Carrara Fm, found in the Saddle between peaks and below the ridge of Gold Ace Lmst Mb of the Carrara Fm (Chambless at Marble Mts) at the foot of the left Peaks. The Echo to Eagle Mt Shale interval (Latham of the Marble Mts site) also is exposed in a series of draws down and two the left (marked by x's) in this photo and runs under the Gold Ace to the right into the saddle

Slab from Saddle of limonitic, silty beds that are from the Echo to Eagle Mt interval. Could be some of what they call Thimble Lmst Mbr for beds in the upper part of the Latham Shale (there are similar unnamed limestone beds in the Latham at the Marble Mt site we visited. Looks to be some interesting material that might include some of the Peachella found at this site. I have specimen from here that I will fit in here later of this rare of which only a few complete ones known. This spot looks like it has potential for more material but I did not find any complete ones this trip, still interesting slab.

View looking back to where the first two shots at looking back here to this saddle were taken. in background just above flats are the dipping Lower Cambrian Zabriskie (dark brown) and the Eagle Mt to Echo Shale and Gold Ace Limestone interval (gray with two reddish resistive beds probably the Thimble Limestone Member (like I am standing on here) and the Gold Ace Lmst at the top of the Carrara Fm.

Joe collecting Olenellids in the Eagle Mt Shale Mbr of the Carrara Fm. Basically this equals the bottom two-thirds or so of the Latham at Marble Mt. Most of what we were finding in the Echo to Eagle Mt Shales were Olenellus terminatus, again whole ones rare but a few were found that day. (have a few from other trips which I will stick images for you later).

Views from last photos of the lower Cambrian Zabriskie to Eagle Mt, Thimble Lmst, Echo Shale, Gold Ace Lmst interval. Second photo is good panoramic shot.

The gang collecting that day , left to right, George Ast, Geoff Thomas, Joe Devera, Mike Lewsader, Russ Jacobson, Dennis Whitney. With Lower Cambrian and Nopahs in background, on road to Emgigrant Pass (to right).

One more look back at the Saddle. of the Gold Ace Lmst, Echo to Eagle Mt Shale interval of the Carrara Fm

Our location on road at the pass where these last photos taken from.

back on road again overview map.

on 127 heading south from the Nopah Range stop.

On Friday we made the start of the long drive back to Illinois but we did one more drive on old 66 thru Amboy, Cadiz and the pass of the road, that will be my last post of the trip...

[trilobiteruss]

On Friday we made the start of the long drive back to Illinois but we did one more drive on old 66 thru Amboy, Cadiz and the pass of the road in the southern Marble Mts to look at the core of the mt and see if there were any Cambrian units in the road cut in pass. (there were not).

past the main and sub vents that were blown out.

We stopped to look at the lava flow at the Amboy crater. Next few photos in the lava field and crater.

We looked around at the 800 year old lava flow and the crater.

Approaching the southern Marble Mts one more time on old 66 at Chambless (right north of Cadiz)

Approaching the pass on old 66 in southern Marble Mts.

Climbing road to pass in Marble Mts (same as map view just before.

Climbing into the pass in Marble Mts on old 66.

In the pass at southern Marble Mts on old 66. The core of pass was granitic, no sedimentary rocks. Both approach and leaving talus covered any sedimentary rocks here so we did not see Cambrian outcrops — would have been too easy compared to where we collected ha ha.

That is the trip. I will take a few photos of some of the slabs with parts I collected at the two days in the Marble Mountains, I did not find any whole bugs even though I have lots from here (Marble Mts and Emigrant Pass) as I mentioned whole ones are pretty rare even with an experienced crew as we had. But I enjoyed looking at scenery, the thrill of the hunt and seeing the geology up close and personal.

Edited March 12, 2014 by trilobiteruss

[trilobiteruss]

Ok this is not gonna be as nice and neat as I like but the darn file size limits on photos in each message bit me. So this is gonna be separate. Here are some bugs from the same locations (or similar)

First from the Latham in the Providence Mts (now closed to collecting) is another Olenellus fremonti similar and about half length of Joe Deveras found at our Marble Mt location on this trip. This shows what final prep can look like.

Olenellus (Mesonacis) c.f. fremonti (ancestral form)

Latham Shale, Providence Mtns. 3 1/16" in length including tail spine.

One of the thing I and a few others found for loose heads (maybe 1 for every 20 or 30 of the Olenellus fremonti heads) were cephalons of the rare Bristolia insolens known from the Marble Mt site. Only a handful of complete ones are known. George has yet to find one complete one in over a 100 trips plus (120 or 150 I forget how many he has been at the Marble Mt site). Below is my rare complete specimen (not found on this trip by the way) in my collection. I will post photos when I have time of the heads I found this trip.

Bristolia insolens (with a partial Olenellus fremonti present also!!!)

Lower Cambrian, Latham Shale,

Marble Mountains, near Cadiz, California

Next I am going to post things which have come from the Emigrant Pass site. I was not fortunate in finding whole bugs there this trip, again only a few Olenellus terminatus specimens (maybe 3 were found by the 6 of us collectively this trip. On some spots here (the area on north side of road we did not visit) a few more whole ones are encountered but we tried a new spot this trip that George and us agreed was worth trying. But even then whole specimens usually require most of day to find several.

Here is two whole ones of about 6 I have of this species from Emigrant Pass. The rocks are a bit stretched and you see it in some of the specimens:

Olenellus terminatus

Olenellinae Walcott, 1890

Olenellidae Walcott 1890

Echo Shale Member

Carra Formation (Pioche Shale), Lower Cambrian

Nopah Range, Emigrant Pass

Inyo County, California

Both have nice pygidial or tail spines

Next are two bugs very rare at Emigrant Pass but worth mentioning, we did not find any that I can say I recognized (definitely none whole)

First a very, very rare Olenellus species of which only few specimens known:

Olenellus transitans

Lower Cambrian

Echo Shale

Emigrant Pass, California.

This trilobite measures 1.5 inches and resides on a 7 x 4 x 2 inch slab

Finally the rarest of rare, just a mere handful known complete (parts can be found like in slab I found in the saddle and related photo of that slab with parts), here is that photo again which I think has some parts from this bug:

Peachella iddingsi Walcott, 1884)

Carrara Formation, Echo Shale Member, Late Lower Cambrian

Tecopa Hot Springs, California

Edited March 12, 2014 by trilobiteruss

[trilobiteruss]

Note I will later post some slabs I collected of Olenellus fremonti heads mostly and some of the Bristolia insolens heads I found at the Marble Mt site later when I have time, but this took me most of afternoon and evening to do and I am just plumb tired and need to get to bed. I will have to find time to photograph specimens but with bad weather tomorrow (snow storm maybe) not gonna be a sunny day to do that. So later. Enjoy the trip I hope some of you find the bit of virtual trip here enjoyable.

[PRK]

Oohh I love insolens. did you find them?

Edited March 12, 2014 by PRK

[trilobiteruss]

Oohh I love insolens. did you find them?

I found a bunch of heads, some rather large. I just have not had the time to photograph them yet. So I put up my very rare whole one from same site to show what a complete bug looks like! They are definitely one of the special Bristolia species.

[squalicorax]

Very nice report. I feel like I was on the trip with yall!

[trilobiteruss]

Very nice report. I feel like I was on the trip with yall!

Good I am glad you felt that way. I like it when others give reports like that for places I cannot always get. This was a fun long anticipated trip (3 years in planning, each year after Tucson things never worked right, they did this year!). As a retired stratigrapher, geological mapper and paleontologist going to the place where so many of my lower Cambrian trilobites came from was a dream come true. I learned much about the geology, rarity of my specimens and had a plain great time with some great friends. Hope to do it again in a year or two if all works...

[Auspex]

This trip report is a Magnum Opus! Thank you!

[cowsharks]

Very very nice. Thanks for taking the time to post all the pics, both the scenery and the rare bugs.

Daryl.

[Scylla]

I've been to the Marble mountains site, and this trip report is better than being there!

[trilobiteruss]

I would like to be there again though..... lot warmer than Illinois right now after another March snowstorm... he he

[Miguel]

Love this trilobites. Thank you friend

[Wrangellian]

Great report - very informative, and the landscape down there is wonderful. Wish I could go sometime!

[trilobiteruss]

Thanks, I love the landscape, it is worth visiting....

[trilobiteruss]

For those wanting to know more about areas of the southern part of the Marbles I visited (south of the Trilobite Wilderness area here is a good BLM link:

http://www.blm.gov/ca/st/en/fo/needles/rock.html

Towards bottom is info about Marble Mts area you can collect and you saw us drive to (Chambliss to Cadiz, south part of the end of mts)

6. Marble Mountain Fossil Beds. Amboy DAG

One of the classic Cambrian trilobite fossil sites in the western U.S. is located at this beautiful outcrop in a 60 foot thick formation over 550 million years old. Trilobites were small marine crustaceans that resembled modern day horseshoe crabs. You can identify the site by the quarry holes and pink, dark green and light brown shale spread along the hillside. By splitting the shale you stand a good chance of finding a complete trilobite. This area can be found by taking historic route 66 to the town site of Chambless then taking Cadiz Road approximately 4 miles. Turn left on the first dirt road and park near the base of the forth ridge and hike the remaining ¾ of a mile to the site.

Over the years this site has been used heavily and it is recommended that only one trilobite per person be removed.

7. Marble Mountain Rock collecting area

In addition to many Trilobite fossils found here, this rock collecting area yields green epidote, dolomite, chrysocolla, chalcedony, serpentine, marble, garnet and specular hematite, iron and kenatite, chalcedony crystals, geodes and gold. You can access this site by taking one of the many dirt roads that lead into the area from Route 66 in and around the town of Chambless.

Here is a map of area you might find helpful....

It is part of the Cadiz Summit Topo Quadrangle.

[RCFossils]

Awesome report Russ. Yet another site to add to my bucket list.

[Wrangellian]

Sounds like it's been hit hard and will only be moreso with more exposure online! Maybe not worth the trip if you are asked to only take one trilo, unless there are other sites or other reasons to travel to those parts...

[Scylla]

Sounds like it's been hit hard and will only be moreso with more exposure online! Maybe not worth the trip if you are asked to only take one trilo, unless there are other sites or other reasons to travel to those parts...

When I went with my family it was 119 degrees F, and between the three of us collecting we only found one trilobite anyway before our bodies started shutting down from the heat.

[JimB88]

you owe me a new keyboard...I drooled all over this one!

Very good report and those bugs are awesome!

[Wrangellian]

When I went with my family it was 119 degrees F, and between the three of us collecting we only found one trilobite anyway before our bodies started shutting down from the heat.

I guess you need to time it right for tolerable weather, if possible. I'd still love to find one trilo at least - better than nothing, and could then say "been there, done that, got this".

[Scylla]

I guess you need to time it right for tolerable weather, if possible. I'd still love to find one trilo at least - better than nothing, and could then say "been there, done that, got this".

I agree! But I wasn't the one who found it. I'll go back one day...

[trilobiteruss]

Sounds like it's been hit hard and will only be moreso with more exposure online! Maybe not worth the trip if you are asked to only take one trilo, unless there are other sites or other reasons to travel to those parts...

Given my experience you are lucky to find one whole trilobite so maybe not as important.