LAS CRUCES, N.M. (AP) -- The Robledo Mountains' reputation as one of the world's most important landscapes of pre-dinosaur fossil trackways likely will be enhanced by another discovery — petrified wood slowly emerging from the desert floor.

""There are just so many types of fossils here, it just staggers the mind,"" said Jerry MacDonald of Las Cruces, the amateur paleontologist who discovered the Permian Period fossil trackways in the late 1980s and more recently found the dozens of locations with petrified wood.
MacDonald told the Albuquerque Journal on Sunday that he believes that time and erosion are causing an ancient forest to emerge from the ground ""that I am just finding the top of.""
MacDonald and others are hopeful that the latest find will generate momentum in Congress to pass legislation to carve out a 5,300-acre portion of the southern Robledos as a national monument to protect the Paleozoic Era trackways.
""The fact that the area contains evidence of so many of the members of an Early Permian non-marine ecosystem preserved in one relatively small area like the Robledo Mountains is unique in the history of paleontology and makes the proposed national monument extremely significant,"" said Sidney Ash, a retired paleobotanist and adjunct professor at the University of New Mexico.
The Permian Period stretched from about 290 million to 248 million years ago, and it represented the last chapter of the Paleozoic Era. The Permian period ended with a mass extinction of species across the planet and ushered in the age of dinosaurs about 70 million years later.
Spencer Lucas, interim executive director of the Museum of Natural History and Science in Albuquerque, said MacDonald's find helps develop a complete picture of an ancient ecosystem.
""Big picture, you've got one of the world's most important footprint localities, and now you've got an extremely important record of fossil plants and woods,"" said Spencer, who has written extensively on Robledo fossil finds.
While some commercially sold petrified wood has been completely mineralized — it's original cell structure replaced by minerals over time — some samples from the Robledos still retain preserved wood cells, which makes them valuable for research.
The quantity of sites where petrified wood has been found in the Robledos also is important ""because it gives us such a big sample of the trees that were growing there,"" Ash said.
""Although the trackways are very significant and deserve protection, the fossil tree trunks are important because there are so few deposits of petrified wood of that age known in the world,"" Ash said.
MacDonald began doggedly hunting fossils in the Robledos after his first trackway discovery in 1987. About 2,000 specimens from the Robledos, renamed the Jerry MacDonald Paleozoic Trackway Collection, are housed at the New Mexico Museum of Natural History and Science.
MacDonald says he has found more than 20 sites with various amounts of petrified wood. He believes some fossils may stretch 20 to 30 feet below the ground.
Several of those, previously examined by paleobotanists, have been reburied, so finding them would be extremely difficult. Only MacDonald knows the GPS coordinates of any of the sites.
The wood's research value is greatly diminished if it is removed from the ground, where it can be placed in a geological context. Plus, said MacDonald, the removal of small pieces of petrified wood would make it harder to find larger specimens.
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