Jet Benchmark

After locating Low & Broad Benchmarks, we decided to make it a trifecta and bag Jet Benchmark.  At the Black Rock exit off I-15 we took a dirt road heading west towards the Virgin River Gorge for about .5 of a mile and parked at the overhead power lines.  We certainly could have driven further (the road ends at a corral) and cut the hiking distance considerably, but we felt like getting some exercise and ended up making this about a three-mile roundtrip excursion.  This actually turned out to be a fun adventure even though we climbed the wrong hill and had to traverse along the ridgeline for an additional quarter mile to reach Jet Benchmark.

We're a couple miles west of Broad Benchmark on our way to Jet Benchmark (slightly right of center) . . .
 We decided to walk rather than coat the underside of our truck with mud

Even though Redstem Filaree is an invasive weed, it has some really pretty flowers

Never walk too close to a cholla cactus . . . They are called jumping cactus for good reason
Even a slight tap and you will feel the pain as the spines cling to your clothing or skin . . . ouch!
Just ask Allison!

According to the GPS coordinates, Jet Benchmark should be on top of this rocky hill

Fremont's Phacelia blooms March through June 

Desert Globemallow were blooming on the southeast facing slope

There were several seashell fossils embedded in the limestone that made up the cliff layers

Well, guess what?
Jet Benchmark was not on top of the hill . . . Kent said we had another .25 miles to go!
(It ended up being on the peak in the center of the picture)

More interesting rocks and another seashell fossil

Finally!  Jet Benchmark (Along with its two Reference Markers)

Jet Benchmark was placed here in 1962
It is labeled as a Traverse Station . . . we've never seen one like this before!

Now we are heading down to locate the Azimuth mark . . . hmm
I-15 through the Virgin River Gorge was competed in 1973, eleven years after the surveyors placed the Azimuth Mark. GPS coordinates show it located between the north & southbound lanes . . .
 You guessed it, we didn't find it! 

Looking back up . . . it was a steep rocky descent

If only this old rusty can could talk . . .

As you can see, Jet Benchmark really wasn't where we thought it should be,
 but that's okay, it made for an enjoyable hike!

 

What a fun half day of hiking!  Not only did we recover three benchmarks, we also got Mike intrigued with the fun of researching and learning the history of how the surveyors placed their benchmarks, reference marks and azimuths for these shiny disks.  Now Mike wants to understand the "madness" as to how they decided where they were going to place them . . . good luck, Mike . . . we still haven't figured that one out!

Low & Broad Benchmarks

Our friend, Mike, who was visiting from Germany, asked if he could make our garage a base camp while he spent some time in the area.  He is trying to "nail down" a job and find a place for his family to live as they make plans to relocate back to the St. George area.

We were showing him our blog and telling him of how our friend Tom's passion for locating benchmarks had rubbed off on us.  It didn't take Mike long before he became interested in the history and the "why" behind where surveyors placed them.  Since we didn't have much going on, for Saturday, we quickly located a few along the Utah/Arizona border and made plans to go recover them.  I guess it was a successful day because Mike now has the "benchmark bug"!

We're south of St. George . . . just across the border in Arizona  

The little bump on the left is where we are headed

Mike and Kent standing at the benchmark . . . Kent is explaining how
the GPS coordinates help us locate the Benchmarks, Reference Marks and Azimuths

Low Benchmark was placed here in 1953

Remnants of the wooden tripod used by the surveyors

This is one of the two Reference Marks we located
The azimuth is supposed to be near the curve in the road . . . we're off to find it next!

How 'low' can you go! If you know Kent, he isn't very flexible . . . neither was the fence!

The Mt. Trumbull Road probably wasn't much more than a jeep trail in the 1950's . . .
We located the azimuth witness post (click on picture for better view), just off the west side of the road . . .
The azimuth was supposedly 21ft east of the post . . . that would put it almost in the center of the road
Guess this one's been "gone" for many years!

Next, we drove to the Black Rock exit to locate a 1921 marker, using GPS coordinates 

It's almost hard to believe that it is still here 102 years later!
(Guess that $250 fine scared some people!)

 

Off to our west we noticed pink ribbons hanging on some creosote bushes, so we decide to check it out . . .       We were surprised to see it was another benchmark! Broad was placed here in 1960

A little to the south we found Reference Mark #2 which meant there should be a #1 . . .
Or so we thought, but we couldn't locate it . . .
We later learned that the 1921 mark was used as Reference Mark #1

If you're interested in seeing Low Benchmark for yourself, follow River Road until it turns from pavement to dirt at the HWY 7 overpass.  Reset your odometer and travel south for six miles (Mt. Trumbull Road).  Park your vehicle and head west up a small knoll for .3 of a mile.

For the Broad Benchmark and the 1921 marker, take the Black Rock turnoff from I-15 and head east until it dog legs a hard right and turns south.  At the dog leg continue east on a different road for approximately .3 of a mile to were three roads converge coming in from the north.  Take the center road for .1 mile.

Dark Benchmark

Finally, we made it out for a hike!  Between the weather and an unexpectedly busy season of life, we just haven't been able to fit in an adventure. (Okay, we haven't tried "super hard" to do so!) So, when we saw the skies were going to be clear and the temperature around 60­­°, we quickly searched for a hike that was close to home.

Lately, it's become common practice to open the National Geodetic Survey (NGS) Data Explorer and look for local benchmarks that we haven't recovered.  They're getting fewer and farther between, but we were able to locate Dark BM south of St. George.  It looked like we could reach it without slogging through muddy roads and so off we went on a Friday morning whim!

We are headed for the "pointy" butte . . . Dark BM is on top
We could have driven to the base of the butte, but decided to park the truck and walk the last mile . . .
Afterall, we're out here to get some exercise!

We quickly located the Azimuth Mark using the surveyors directions (see the black arrow)
Hard to believe their "witness post" is still in place after 70 years

1953 seems like recent history!  It must mean we're getting old to be thinking this way! 

Continuing down the road . . . we were so thankful it wasn't muddy . . . we've had a lot of rain this winter! 

Leaving the road, we hiked up through black lava rock . . . some coated with desert varnish

 This Cholla Cactus Skeleton stood out amongst the creosote bushes 

Finding the surveyors tripod in shambles made locating Dark BM very easy (yellow arrow)

We found the Dark Triangulation Station, or BM, in good condition, along with both reference markers

Heading back down . . .
The yellow arrow points back to the Azimuth Mark, near where we started

We made a detour, to the west, so we could check out a dry waterfall
 in a small canyon next to the road (see picture above) . . .
It turned out that the waterfall was "unremarkable". . . 
But, hiking to it provided us with a way to extend our short outing

A "family" of barrel cacti were growing on a ledge 

Almost back to the truck . . . Man, it felt good to get outside and do some exploring!

While this hike ended up being only about two-miles round trip (you could make it longer or shorter depending on where you decide to park), it provides a relatively remote feeling for a hike so close to town.  If you're interested in finding Dark BM, for yourself, just take the Black Rock exit south of St. George and head towards the Gypsum Mine.  Reset your odometer, at the mine, and proceed another 1.5 miles (just past a cattle guard) and take the side road that heads west for another 1.5 miles.