Potato Patch Thundereggs and Geodes

Wiley’s Well Rockhound District - California

by Delmer G. Ross

For those of us who are fortunate enough to be able to visit the Wiley’s Well rockhound district (near Blythe, California) on a regular basis, geodes and nodules are rather commonplace.  Having visited the Potato Patch, the Hauser Beds, the Straw Beds and other nearby thunderegg-producing areas of the Colorado Desert many times, we have so many piles of them in our back yards waiting to be cut open that we tend to treat them casually.  We fail to realize that others frequently regard them with something akin to awe.

With the help of his very observant father, a rockhound named Joel F. Hauser discovered the Potato Patch in the early 1930s.  Twenty-five years earlier, the elder Hauser, George, had been a partner in Hauser & Giddings, a Colorado Desert freight line operating mainly between the Southern Pacific Railroad at Glamis and the Palo Verde Valley town of Blythe.  As he drove heavy, freight-laden wagons across the desert, he followed two basic routes.

Road to Potato Patch

The preferred road led through Palo Verde Canyon.  It was the shorter, more direct route.  It was, however, also subject to flash flooding and major washouts, especially during the usual late summer monsoons.  The alternate route, used mainly when flooding in the gorge closed the canyon road, led from the little community of Palo Verde, near the Colorado River, west to the southern stretch of the Mule Mountains.  After crossing over a low pass in the Mules located only a mile or so east of the present-day Coon Hollow Campground, it continued west, through what today is known as Ashley Flats, to another low pass some eight road miles away, adjacent to today’s Potato Patch.  Then, turning southward for a mile or two, and then southeastward, it eventually rejoined the main Blythe-Glamis road.



Forced to use this alternate route twice a week for sometimes two or three months every year, George Hauser had ample opportunity to note the odd, spherical rocks that were common in several places in the low hills where the route turned southward.  He even reflected on the possible reasons for their roundness, without reaching any conclusion.

More than two decades later, when his son, Joel, who had become a rockhound, showed him some of the nodules and geodes he had been collecting, George remembered those round rocks he had seen in the desert during his freighting days.  Perhaps they had been geodes!  He urged his son to search the area.

Wiley’s Well Rockhound District

Although Joel wondered if an exploratory trip to the Colorado Desert would really be worth the time he might need to spend on it, in the early 1930s he eventually decided to give it a try.  He bought a well-used Model A Ford for $37.50, loaded it with supplies, and, with his father acting as guide, set out for the desert.  Although the landscape had changed since the senior Hauser had last seen it more than 20 years earlier, they experienced no trouble locating the region of the strangely rounded rocks.  Moreover, just as his father had explained, in many places – especially in depressions – the ground was literally covered with very dark colored round stones measuring anywhere from an inch to six inches in diameter.  As Joel looked around, he noticed several that were even larger.  He had reached an area just north of what today’s rockhounds call “The Potato Patch.”

The young rockhound climbed out of his Model A and gathered up a few of the stones.  Then he got out his rock hammer and gave the first of his rocks a hefty thump.  Not much happened, except that the dark coloring scratched off where he had struck the surface, showing that the stones were coated with desert varnish.  He tried again, using more force.  This time he succeeded in cracking open a fine “thunderegg,” as nodules and geodes are sometimes called.  The men took a whole carload back home with them.

Potato Patch geode cracked open in the field.

Joel then got busy cutting and cracking open what they had hauled back.  Most turned out to be solid-centered nodules.  They were his favorites because of the great variety of interiors, with fortification and water-level banded agate of various colors and often containing crystals that had grown together into a solid mass.  Some even had what appeared to be solidified seascapes.   Others were hollow geodes, often lined with quartz or calcite crystals.  Having determined that he really had stumbled onto an easily reached and plentiful source of thundereggs, he publicized his discovery so that others could enjoy collecting there as well.

Hauser’s fellow rockhounds soon began pouring into the region.  Some doubters found it hard to believe his account, but they soon learned that his discovery was everything that he had described.  There were so many thundereggs that for two or three years collectors searched only the surface of the land in the region they were beginning to call “Hauser's Hole.”  Once the surface material in one area had been fairly well picked over, rockhounds would just move on to another spot.  In time, though, productive locations became ever more difficult to find, and a few disgruntled collectors began to grumble and gripe about how Hauser’s Hole had “played out.”

Judging by what his father had told him and what he himself had observed, Joel guessed that there should be other thunderegg-rich areas not far from his original discovery.  Therefore, in 1937 he determined to go to the west side of the Black Hills and work his way east in search of new deposits.  One evening as he was setting up camp near a wash only a mile or so from Hauser’s Hole, he noticed a layer or two of thundereggs in the light green colored volcanic ash at its edge.  He further discovered that by digging into the bed of ash, which was just under the surface of the ground, he might find even more.  The next day he and two of his friends started digging in earnest.  The result was astounding.  As Joel explained, “We dug out so many geodes we couldn’t haul them all home.”  He had discovered the Hauser Geode Beds, which were to become far better known than his first discovery.  Although they are less than one air mile apart, today the Potato Patch and the Hauser Geode Beds are correctly viewed as two separate and distinct collecting areas, mainly because the thundereggs they produce are different.


Hauser’s Hole did not become “The Potato Patch” until a number of years after the discovery of the Hauser Beds.  While at Hauser’s Hole all rockhounds had to do was to identify and pick up the geodes, at the Hauser Geode Beds they generally had to dig into volcanic ash to locate them.  It was a difference that caught the attention of rockhounds and others right away—often in the form of aching muscles!  Some, though, reasoned that if geodes could be dug out of volcanic ash only an air mile or less away at the Hauser Beds, perhaps they could be found in and dug out from similar ash at Hauser’s Hole.  They gave it a try, and sure enough, they located a plentiful underground supply. 

Heart shaped geode

There was a problem, though.  What should the rediscovered site be called?  With the Hauser Beds only a short distance away, to continue to call it Hauser’s Hole seemed confusing.  According to a popular version of the naming process, the green-colored, bumpy-surfaced, oval geodes and nodules being dug out looked very much like green potatoes.  Thus, “The Potato Patch.”

Despite its odd-sounding name, The Potato Patch has been a very productive rockhound area for nearly three-quarters of a century.  In addition to thundereggs, readily available collectible material includes various types of jasper and agate, calcite crystals, and some rhyolite – I call it pecky rhyolite – full of crystal-lined cavities that makes beautiful slabs.  Although relatively rare, naturally weathered star and biconoidal thunderegg cores can be found throughout.  Furthermore, there are several outcrops of rather weather-fractured antigorite serpentine located about one tenth of a mile west of the eastern Potato Patch road.  The serpentine at 33°22.975' N by 114°58.237' W sometimes contains spectacular red streaks.  Some equally striking thundereggs have been unearthed in the same area.  A vein of barite is located at 33°22.933' N and 114°58.102' W.  Observant collectors will find much more. 

Rockhounds planning to visit the Potato Patch will find a vehicle with four-wheel drive and high clearance to be helpful, but it is not essential.  Provided it is not so low to the ground that it nearly drags, a careful motorist can drive the family sedan to within 20 or 30 yards of some of the best digs, and a little walking can take one to many more.

To visit the Potato Patch, from Blythe, California, drive west on Interstate Highway 10 approximately 16 miles to the Wiley’s Well exit, then 13.3 miles south to the Riverside-Imperial county line at 33°25.800' N and 114°54.180' W.  Wiley’s Well Road becomes Milpitas Wash Road in Imperial County.  Immediately south of the county line, at 33°25.794' N by 114°54.182' W, turn right onto the track that angles southwest across the desert pavement.  This will lead you slightly more than a half mile to what is generally known as the Black Hills Road at 33°25.429' N and 114°54.620' W.  Bear right, and continue on the most traveled road past a metal signpost marked “Ashley Flats” straight ahead and “Gerdes Trail” to the north.

Continue driving in a generally westerly direction to a second metal signpost, this time marked only “Ashley Flats,” at a fork in the road located about 4.5 miles from Milpitas Wash Road (or Wiley’s Well Road).  Your GPS coordinates should be close to 33°24.825' N and 114°58.145' W.  To continue toward the Potato Patch take the south fork of the wye and cross the gravel bed of the Black Hills Wash.

In one mile you will reach another junction at 33°24.121' N and 114°58.679' W.  Known as Potato Patch Junction, this is where those going to the Hauser Beds turn off the road you have been following.  One short stretch of road just before you reach the intersection is rough, but if you pick your course carefully and take it slow and easy, you should have no trouble. 

Drive southward – straight ahead – from Potato Patch Junction six tenths of a mile to a hardly noticeable road that leads off to the left to the Owl’s Roost area at 33°23.567' N and 114°58.811' W.  There, if you look at the upper western slope of the hill to your left you will see sign of disturbed earth.  This marks the northern extreme of the Potato Patch.  Continuing southward across desert pavement, about three tenths of a mile ahead is a fork in the road at 33°23.357' N and 114°58.766' W.  To continue exploring the Potato Patch, proceed southward as much as a mile or so on either road.

If you take the east fork, you will reach a junction two tenths of a mile ahead, at 33°23.232' N by 114°58.589' W.   To continue on the eastern Potato Patch road, turn left.  The first serpentine outcrops are about four tenths of a mile ahead.  Of course, you will drive by several thunderegg digs before you get that far.

Geodes and nodules from the northern reaches of the Potato Patch tend to have more colorful agate interiors than those collected from the southern portion.  Although they may be found almost anywhere, those found in the southern area tend more toward hollow interiors with calcite crystal linings.

Because summertime temperatures often soar to 115° Fahrenheit and more in the shade – and there is precious little shade available – the best time to visit the Potato Patch thunderegg beds is from late October to late March.  Be sure to take plenty of water and whatever else you may need.  Accommodations, services, and supplies can be obtained in Blythe, about 35 miles northeast.

Delmer G. Ross, is a Professor of History at La Sierra University
Photographs by Karen A. Ross

Ross is the author of the Gold Road to La Paz which covers the Bradshaw Trails and many rockhound sites. This is a rare book that's hard to find used; we now have new books in stock get one here.

In October of 2016, DesertUSA visited the Potato Patch. The video we made can give you an idea of where to dig for geodes. Watch for green tinted ground - it's indicative of volcanic ash. And that, in many cases, is where geodes and other rocks can be found.




Coon Hollow Campground


There are hotels and motels in Blythe, with something for every taste and price range. For more information and a complete list, click here for rates, availability and reservations online.


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