At the Arizona-Sonora Desert Museum''s paleontology lab, the air scribe has become the workhorse of fossil preparation. The discovery of a large sauropod dinosaur in the highly indurated sandstones of the Mid-Cretaceous Turney Ranch Formation southeast of the museum posed numerous technical problems for our lab staff. Most troubling was the removal of vast amounts of sedimentary rock, which was both very tough and firmly cemented by silica to the softer, calcite-replaced bones. chippershredderiowa Experimenting with a number of hand tools, grinders, hardware-store engravers, and rotary devices, we happened upon a Chicago Pneumatic Air Scribe (see supplier''s address on page 421), and it has since become our primary lab tool on this project. We now have five Chicago air scribes, chippershredderiowa and chippershredderiowa and progress on our dinosaur has been extraordinary. One large and complex midback vertebra, which had been crushed during fossilization, took seven months to prepare with the scribe, but it chippershredderiowa was in the middle of a 150-pound block of sandstone. Not only was museum preparator Yolaikia Sciole able to remove this complex and fragile vertebra without damage, but ultimately it was prepared chippershredderiowa from the inside out, exposing most of the internal bone chippershredderiowa structures, including arterial and nerve canals and never-before-seen pneumatic structures that lightened the bone in chippershredderiowa life. Most of the bones in this vertebra are no more than 0.25-inch thick and are replaced by easily cleaved, fragile calcite. The air scribe, and a light touch by the preparator, did the trick.

WORK AREA: Gulf of Mexico.OCEAN HERITAGERIG DESIGN: Friede & Goldman L-780CONSTRUCTION: Far East Levingston Shipyard, Singapore, 1981.PERFORMANCE: Water depth--250''; Drilling depth--20,000''.QUARTERS: 84 persons.HULL: 180'' x 175'' x 25''.VARIABLE LOAD: 4,449 kips.HELIPORT: 62'' dia.STORAGE: Mud & Cmt Bulk--6,000 cf; LiquidMud--1,600 bbl; Water for Drilling--5,500 bbl;Potable Water--1,000 bbl.DRILLING EQUIPMENT: Drawwork--Nat''l chippershredderiowa 1320;Pumps--Nat''l 12-P-160; Prime movers-four Cat.D-399; Rotary Table--Nat''l 37 1/2"; Top Drive--Varco BJ.

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