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Fruitland Fm: New Mexico
 

When working at Ah-Shi-Sle-Pah wash in 1921 the famous dinosaur collector Charles Sternberg was so taken aback by the beauty of the rocks, he later wrote that in his mind, the area should be designated a national park. This area, which I call "mushroomland" is just behind where we camp. Here the hard sandstone concretions cap softer rocks to make strange and surreal shapes, flanking both sides of a small arroyo.

The Fruitland Fm was deposited on a lush coastal floodplain, close to the Western Interior Seaway. Prominent coals distinguish the Fruitland from overlying beds; West of our field area, these coals are especially thick and are commercially strip mined.

Ash beds found within the Fruitland Fm show that it was deposited from about 75.56Ma to 74.6Ma (Fassett & Steiner, 1997). The lower part of the Fruitland Fm, the Neh-Nah-Ne-Zad Mbr is very poorly fossiliferous, so we rarely spend much time there, preferring instead to hunt in the overlying Fossil Forest Mbr.

As the name suggests, the Fossil Forest Mbr is full of fossilised wood, ranging from coaly beds, with fine fossil leaves, to large silicified tree trunks, still in life position. the Fruitland Fm is overlain by the Bisti bed sandstone of the Kirtland Fm.

We collect mainly at Ah-Shi-Sle-Pah wash, which includes the very top of the Fruitland Fm. These rocks are especially rich in dinosaur fossils, and have been historically collected since the 1920's


Our campsite at Ah-Shi-Sle-Pah. We have used this spot for three of the four years I have been out collecting with Bob.
It's pretty bleak, and gets terribly muddy when it rains. 'Nice and secluded though, with lots of bats at night.

Bob and I hike out across the south side of Ah-Shi-Sle-Pah. (2006)

The lack of any vegetative cover in the wash means that dust storms are pretty common. We took this photo just after a dust storm blew through (you can see the remnants in the distance. At times like these, all you can do is hide behind a rock and cover your eyes, nose, and mouth.


This photo was one of a series taken during Sternberg's expedition in 1921. Was this the typical field attire for his Navajo assistants?


In 2003, my dad (sitting) and Bob re-enact the pose of Sternberg's assistants. In 82 years, you can see there's not been much erosion to Sternberg's hoodoo ( the geological name for these thin spires of rock).


In 2004, Bob found the femur of a theropod dinosaur weathering out right next to Sternberg's hoodoo.

A close up of the femur, from a small tyrannosaurid or large ornithomimid


Here I'm digging out a hadrosaur maxilla (probably a lambeosaurine). In the backgound is "Bob's bloody bluff". The orange sandstone that caps the bluff is called the "Bisti bed" and separates the Fruitland and Kirtland Fms (2003, photo: Bob Sullivan).


Just on the other side of "Bob's bloody bluff" my dad found this bone, probably a pelvic element (2003).

Near the lambeosaurine maxilla, I found this hadrosaur tibia. As part of the sampling effort, we collect every bone that is diagnostic, so even while crushed, this was worth a few hours digging. (2003, photo: Bob Sullivan).


On the south side of Bob's bloody bluff is "Eagle's nest" where we found an exploded ceratopsid skeleton. The flat area you can see in this photo proved to be really rich in turtles. We named that locality "eagle's nest flat" (2003)


"Eagles' nest flat" up close. Bob is hard at work here, collecting turtles and fragments of dinosaurs (2003)


This fine turtle carapace was one of many that we dug out of "eagle's nest flat" (2003, photo: Bob Sullivan).


Toe bone (digit III: middle toe, 1st phalanx) of an ornithomimid dinosaur that I found out on eagle's nest flat. Most of the material here was isolated, but some of it was really nicely preserved. (2003)

Another 1921 picture. This one records a silicified tree stump, still in life position. (image ©University of Uppsala)

In 2006 we rediscovered all of the localities featured in Sternberg's photos. From this we found that on the day that the photographer visited, he followed the crew south along exposures on the eastern side of the wash. (Bob Sullivan in photo)

"Turtle terrace": a locality that was rich in turtle remains. We found so many turtle-rich sites we eventually ran out of names like "turtle town" etc..
This particular site was also rich in large coprolites (fossil faeces).
(2003, photo: Bob Sullivan).

This is one of the coprolites from turtle terrace. Note the classic croissant shape.
(2003, photo: W. P. Fowler).

A tyrannosaurid astragalus (ankle bone) that we found near camp (2004).

One of the most common dinosaurs in the Fruitland Fm is Pentaceratops sternbergii. This chasmosaurine ceratopsid is related to the Triceratops that John Scannella & I work on up in the Hell Creek Fm, MT. This photo was taken of a cast on display at the New Mexico Museum of Natural History & Science, Albuquerque.

A bronze model of Pentaceratops guards the entrance to the museum. One particularly hot day, a foolish father lifted his child up to ride the beast. He soon learned why this was a bad idea.

A huge specimen of Pentaceratops is on display at Sam Noble Oklahoma Museum of Natural History. This skull is in the Guinness Book of records as the largest dinosaur skull in existence... although the Torosaurus at the Museum of the Rockies must be similar if not larger. Most of the frill of this specimen was reconstructed from plaster, but the face is real. Here Bob attempts a mind meld, while Mike Burns writes down measurements (2004).