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Permian Vacation

Mogollon Rim • Petrified Forest


By mid-March the seemingly interminable winter of ’06 had left me restless. So I decided to take a trip to Arizona to visit friends and family and explore whatever a week would allow. A few days into April I touched down in Phoenix and hit the highway just in time to experience their rush hour. I had been forewarned, and it wasn’t pretty. Phoenix, I’m told, is growing at a rate of 300 people per day and apparently they all brought their cars. But once I’d crawled across town the traffic evaporated and I learned that the 75mph speed limit is for sissies.

The 125 mile drive to Flagstaff is a pretty straight shot and a crash course in the varied topography of the state. With a 5,000 foot gain in elevation it’s uphill all the way. You can easily gauge your elevation by the local flora. One starts in the low desert amid imported palm trees, climbs into saguaro studded hills, and finally ascends to the pinon and ponderosa pine forests of the Colorado Plateau. The climate changed too, I started the drive in a t-shirt and ended in my down parka. My plan to escape the grip of winter was foiled: it snowed two inches my first day in Flag.

Flagstaff is a college town (U. of Northern Arizona) spread at the base of the picturesque San Francisco Mountains, a somnolent volcanic blister towering anomalously over the plateau. At 12 and a half thousand feet Humphreys Peak is the highest point in Arizona, you can see it from hundreds of miles away. There is much of scientific, geological and paleontological interest in the region. I spied Lowell Observatory, where Pluto was first sighted, on the hill above my brother Zack’s house. The USGS is based there. There’s the Sunset Crater lava fields and the Walnut Canyon ruins. Sedona is a short drive to the southwest, the Tuba City dinosaur tracks to the northeast, and of course the Grand Canyon about an hour and a half north. But I’d done all those on previous visits.

I’d brought a copy of Gem Trails of Arizona and earmarked fossil hunting propects along my probable route. GT even listed a local site just out of town above Walnut Canyon, but admitted the pickings were meager. The highest concentration of sites appeared to be about 60 miles southeast on the Mogollon Rim. Zack, a longtime resident and former Forest Service employee, knew the area and my second day in town suggested we head down there. FS maps in hand, he dismissed my economy rental car as inadequate and threw a snow shovel and traction inducing cord wood into the back of his pick-up. Just in case. Packing the chisel I’d smuggled in my luggage and a crack hammer from the local Home Depot we were off.

Arizona is crossed by several anonymous interstates, but the way to really see the territory is traveling its network of fine two lane highways. It was a gorgeous, sunny day as we wound through the Coconino National Forest along the shore of Mormon Lake. We hooked up with AZ87, which follows the top of the Mogollon (inexplicably pronounced MUG-ee-ahn) Rim, the bottom fringe of the Colorado Plateau. This vast feature cleaves the state in two, the high plateau to the north, the low desert to the south. GT lists a half dozen fossiling sites along this route, most down unpaved Forest Service roads, hence the four wheel drive vehicle.

   

     Blue Ridge Reservoir, the Mogollon Rim and MNA  © 2006 Zackery Zdinak



Our first stop was Blue Ridge Reservoir. About four miles down a dirt track a road cut about 10 feet high exposed the underlying limestone. We overshot the indicated mileage but inspected the rock face there before we doubled back. We parked in a turnout and combed the road cut. At first we didn't see any fossils, just little lizards who didn't seem pleased to see us. But a few hundred yards along my brother spotted the first fossil: a big brachiopod. I saw some more of them, and what looked like a cephalopod. I broke out hammer and chisel, but the recalcitrant limestone wasn’t giving anything up easy. I came away with just one partial brachiopod. As GT recommended, we examined the rockfalls downslope of the road, and as warned, this was a perilous course. The slope was steep and the rocks unstable. And they didn’t yield anything. The location, however, was stunning: perched above a jewel-like lake midway up a deeply forested cleft in the mountains. Still, we moved on.

My brother, the real naturalist in the family – albeit with more affection for things still living – knew of an area where he’d seen fossils the year before. We bumped along some 20 miles of twisty Forest Service back roads through remote woods of ponderosa pine, Douglas fir and even aspen. The Rim, he explained, caught more moisture than any other part of the state resulting in a truly florid ecosystem. We picnicked by a beaver dammed stream, kingfishers, hawks and Great Blue herons flapping through. We crossed paths with several groups of elk, and even a family of havelina, the blackly bristling wild swine. And we were lucky with the weather as well: by midday the snow had retreated to decorative drifts here and there in the shade of trees, the roads mostly dry but not dusty.

We finally hit the Rim Road. This was a part of Arizona I had never encountered, and considering its inaccessibility, no wonder. Here the forest spills off the abrupt end of the plateau in a spectacularly ragged crenellation of cliffs. Dark sandstone layers, like wobbly stacks of coins, stagger a thousand feet over the rolling hills of the lowlands below. We followed the Rim another couple of miles to an area where Zack knew the Kaibab Limestone -- the same fossil bearing formation exposed in the Grand Canyon a 150 miles north -- capped the predominant sandstone.

We parked his truck and he led me out into the more open terrain between the road and the cliffs. After a few minutes scouring for patches of exposed earth amid scrubby grass and fallen logs I spotted my first fossil: a golf ball sized brachiopod just sitting there on the ground. Soon we were finding more, especially back near the road where there was more bare earth. Radially ribbed, with a deep central fold that gave them a bi-humped butt shape, the brachs stood out white against the red dirt. We must have found over a dozen in a half an hour, a kid-in-a-candy-store sort of situation. Some were stacked pairs, some had both valves, but few retained the subtle spines jutting sideways off the hinge line. I later identified them as Peniculauris bassi, a Permian brachiopod common to the Kaibab. Unfortunately the day was running late and we had to start back sooner than I’d have liked. But it was an exhilaratingly prolific site. We took a few pictures and the best examples, then left the rest as we found them scattered on the ground.



     Peniculauris bassi at Mogollon Rim © 2006 Zackery Zdinak


On the drive back I checked my Gem Trails and found that the location we’d just left corresponded roughly to their Rim Road Fossils site. It’s a wonderful area, both for the fossils and the views, but not a place to venture without a 4x4 vehicle, a detailed Forest Service map and a check on the snow conditions in the spring or fall (don’t even consider winter).


Before I’d left home I had done some research and contacted Dave Gillette, the resident paleontologist at Flagstaff’s Museum of Northern Arizona. He extended an invitation to show me around a bit if our schedules lined up. So the morning after our trip to the Rim Zack and I showed up at the Geology building on the MNA campus north of town. Dave was more than hospitable. He gave us a tour of two prep labs where his grad students are analyzing new Cretaceous fossils from the Tropic shale of Grand Staircase-Escalante National Monument. They’ve recently unearthed scores of plesiosaurs, identifying four short necked species so far, including two that are new, representing animals ranging from 12 to 50 feet in length. He showed us long jawed skulls, paddles, vertebrae and piles of gastroliths found with the big lizards that he is convinced were swallowed for ballast. And he pulled out a drawer of teeth of various sizes, all functional yet from a single jaw, a unique discovery among plesiosaurs. We leaned over a big block from Ghost Ranch they’re preparing, an articulated Coelophysis distinct atop the massive jumble of bones.

Then Dave showed off his pride and joy – or what was on hand of it – one of the first and most complete therizinosaurs found in North America. This specimen, a new species of Nothronychus, would be the subject of a special MNA exhibit. Most of the fossil was in Utah being cast for display but he brandished the core of what in life would have been a 15” claw giving this biped real Freddy Krueger hands. The Tropic is a marine deposit, so theories on how this terrestrial critter got out to sea range from “bloat and float” to a semi-aquatic lifestyle.

Dave’s wife Janet is the collections manager and gave us a tour of their storeroom. Nearly every geologic period is represented by Arizona fossils. They’re especially proud of their Triassic fossils from the Chinle formation, Kaibab Permian, and Cretaceous mammals. We perused a couple of their many trackway slabs and Janet helped me ID the brachipods we found the day before.

It was a pretty sweet tour, so that our subsequent visit to the fossil exhibits at the actual museum across the road was, frankly, a bit less than redundant. Like most museums, only a fraction of their actual holdings are on display. The MNA presents the rich paleohistory of the Colorado Plateau in comprehensive, elegant, but minimal terms. The museum gives more space to their splendid Native American collections.

I bolted from Flagstaff after lunch and drove 200 miles east into the heart of the Navajo Indian Reservation where a college era roommate was expecting me. I could only sigh wistfully as I drove up Route 191 knowing (as Zack’s Roadside Geology of Arizona informed me) that pearly ammonites nestle in the Cretaceous Mancos shale on Black Mesa to the west, deep within the Rez.

My destination was the dusty little village of Lukachukai at the foot of the picturesque Chuska Mountains.  My host and I spent the weekend hiking beautiful Canyon De Chelly to view ancient Anasazi cliff dwellings. We stumbled into a pow-wow on the campus of nearby Dine Community College where we got to see some great costumes (more Vegas than Pre-Columbian) and dancing. We were also treated to traditional chants, drumming and Miss Navajo Nations singing the Star Spangled Banner…in Navajo!

After a picnic breakfast on the Buffalo Pass overlooking New Mexico's Shiprock formation I headed south. By early afternoon (I kept gaining and losing hours, the Rez being a different time zone than the rest of the state) I reached  the north entrance of Petrified Forest National Park. I wound south through the brilliantly colored badlands of the Painted Desert. I stopped at the overlook for the petroglyphs dubbed Newspaper Rock, but jetted past the turnoffs for ruins. I wanted to see the petrified trees and the locally touted Rainbow Forest Museum. Before long I started spotting clutches of stony logs and soon reached the museum, some 30 odd miles down the length of the park.

After all the hype the “museum” turned out to be a glorified alcove, albeit with some nice fossils representing the local Triassic. There are just a handful of mounted skeletons of big reptiles and a case of smaller plant, amphibian and invertebrate fossils. But if one regards the jumbles of petrified logs beyond the building as an outdoor museum then it’s a pretty grand collection indeed.



Specimens of gorgeously multi-hued wood litter the surrounding hills. Visitors are reminded at every step that pocketing the merest splinter is a crime of far greater expense than buying a piece at the gift shop across the parking lot. But if you’re like me you can’t settle for buying fossils if there is the slightest possibility you might be able to collect some with your own two hands. After a long stroll among the logs with the badlands for a backdrop I beat it for nearby Holbrook, whose famously cheap motels are conveniently clustered along a railroad track where freight trains run all night long. And I mean all night.

I inevitably rose early the next morning, somewhat worse for wear, and after a palate cauterizing plate of huevos rancheros (now I was awake) went to check out the local rock shops. Throw a rock in Holbrook and you’ll hit a rock shop. I hit the biggest one I saw, the supermarket sized Jim Gray’s Petrified Wood Company, right at the turnoff for the park. If the park is a forest, this place is a nursery. The cyclone fenced grounds around the building are fields of stony stumps. Inside petrified wood comes in every conceivable size, polish and price point. They’ve even carved it into tiny Bambi deer figurines. They’ve got lots of other fossils too, on sale or display, and other mineralogical marvels as well.

Gem Trails lists 8 localities for collecting petrified wood and one was a few miles south of town. I headed down AZ77, then took the turnoff for Woodruff. The book advises scraps of wood can be found all long this little road across the scrubby range. I stopped the first place there was shoulder enough to pull over and combed the embankment between the road and the barbed wire fence to either side. I found some rainbowed bits of mineral that looked of the same composition as the local petrified wood, but I wanted to find something with wood texture to be certain. And after a little while I did, scraps to be sure, not much more than petrified wood chips, but with the same brilliantly varicolored banding I saw in the park: milky quartz, yolky ochres and raw meat reds. I also found a couple of branch sections.

I followed that road a few miles further, stopping periodically to scour the shoulder. A wide turnoff for a gated range road offered more room to look, but less to be found, probably because of the spot’s popularity. Two more cars stopped the hour I spent there.  It was windy on that roadside, and sunny (I forgot to put sunscreen on my legs and the back of my knees got like chicken tandoori). And there were nasty little thorns on the brush too, my hands took a beating. But despite the competition I came away with a nicely colorful bag of rocks for my efforts.




From there on it was a leisurely drive on state roads back to Phoenix. I managed to time it so I was in the desert proper as the sun went down. I stopped at a trail head 50 miles outside the city and climbed a ridge thick with prickly pear and towering saguaro cactus. As the sun dipped below the mountains to the west, the moon rose opposite in a lavender sky dotted with flitting bats. The gaps between the whoosh of cars below filled with the miniature bleat of crickets. As I walked back to the car I remembered Zack telling me this was the time of day rattlesnakes went abroad. I didn’t meet one. That would have been too perfect.




A version of this article previously appeared in the November 2006 edition of the NYPS newsletter.