ammonites
10P, Walker Mountain, Martinsburg Fm., Smyth Co., VA (Ordovician of the United States)

Where: Smyth County, Virginia (36.9° N, 81.5° W: paleocoordinates 29.8° S, 61.9° W)

• coordinate estimated from map

• small collection-level geographic resolution

When: Martinsburg Formation, Caradoc (460.9 - 449.5 Ma)

• Total unit thickness = 32.16 m

•Time interval = Trentonian-Maysvillian

• group of beds-level stratigraphic resolution

Environment/lithology: transition zone or lower shoreface; gray shale and shelly/skeletal, gray packstone

• within author's clastic platform facies
• shale (80%) and limestone (20%); shale medium gray to light olive gray in beds 0.15 to 1 m thick; includes several percent very thin beds of siltstone toward the top of unit; limestone is skeletal packstone and laminated calcarenite to calcisiltite, both with abundant terrigenous silt; medium light gray, very thin to medium bedded; commonly in packstone-laminated bed couplets, rare tabular ripple cross-lamination in sets 10-20 cm long

Size class: macrofossils

Collection methods: bulk,

Primary reference: R. D. Kreisa. 1980. Virginia Polytechnic Institute and State University. 1-355 [S. Holland/K. Layou/K. Layou] more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 50618: authorized by Steven Holland, entered by Karen Layou on 18.05.2005