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PBFossilAgae05.tif Pittsburg Bluff Formation (near Mist, Oregon) Late Eocene or early Miocene. I am finding a lot these tubular items in the matrix. Still waiting from the adapter for my good camera, this is from a 5 mpx camera. Since it is a marine environment, perhaps this is some type of Algae? On my 27" screen the yellow ring part has fuzzy hairs protruding. This was taken with a 5 mpx camera and a 10X objective.
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MARINE MOLLUSKS aggregation from the Pittsburg Bluff (Oligocene) and perhaps a bone.....
OregonFossil posted a topic in General Fossil Discussion
Location: where fossiliferous exposures are found in streambanks and in cuts on highways, logging roads, and railways. The type area of the formation is along the Nehalem River near Pittsburg, Oreg., where a highway cut affords a good exposure of its lower part. Exposures of the Pittsburg Bluff Formation are relatively scarce; they are interrupted by broad areas of thick soil cover and dense vegetation. The formation is cut by minor visible faults, and there may be others that are not visible, so the mapping is uncertain in some places. The Pittsburg Bluff Formation conformably overlies the Keasey Formation (late Eocene and early Oligocene) and is conformably overlain by the Scappoose Formation (late Oligocene and early Miocene). Because parts of all these formations are lithologically similar, the stratigraphic position of a nonfossiliferous exposure is sometimes uncertain. New stratigraphic studies indicate, however, that contrary to the opinion of some previous investigators, the Pittsburg BluffFormation is conformable with the underlying Keasey Formation. In Oregon you can hunt the roadside ditches and talus piles for fossils if you are brave enough to face the traffic:) Last time out I was lucky and found a very large piece of the sea floor (about 38" long, 14" wide, 8" deep) as well as about 10 smaller pieces. Today I was working on a 3' by 8' piece using paint brushes to get some of the lose matrix off (to be scanned for various microfossils). Here is what the piece looked like: The Red "T" marks a small piece of matrix that I removed with dental tools. Lots of shell fragments and casts of Mollusks. Not sure what that brown stain. Under the red "T" was something I have not seen before in this matrix. Here is the item (6.7mm x 6.5mm), do you know what it is?: Here is some more information of what has been found in this formation: The Pittsburg Bluff molluscan fauna contains none of the rock dwellers of the littoral zone with the possible exception of Mytilus, and no snails that are known to be herbivorous. None of the mollusks found in the formation, except the turrids, are considered indicative of deep water. No remains of echinoderms or crabs have been found, and foraminifers are represented by two poorly preserved globigerinids. Some fish remains have been found; the teeth identified are of sharks and rays. Welton (1972, p. 168) makes the following statement concerning the shark teeth: ***the lower sections of the Pittsburg Bluff Formation yield numerous teeth of a small squalid shark Centroscymnus and not uncommonly teeth of Raja, Squatina, Odontaspis, Squalus, Pristiophorus, and Notorhynchus. These genera, plus several additional forms, collectively constitute the most diverse assemblage yet known from the middle Oligocene of Oregon. Otoliths from USGS 15310, in the middle part of the Pittsburg Bluff Formation, were identified by John E. Fitch, California Department of Fish and Game, as belonging to the families Congridae (conger eels) and Macrouridae (rat tails), both bottom-dwelling families that typically inhabit moderate (200 m) to great depths (500 m), and, although found in all oceans of the world, are least common in tropical seas (John E. Fitch, written communs., May 23, 1973, and June 18, 1973). From the preserved molluscan fauna, a picture emerges of an infaunal community of filter feeders, detritus feeders, and carnivores living on or within the sediment of the sea floor.-
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starting to look for micro fossils in sediment from the Keasy & Pittsburg Bluff Formation, Questions...
OregonFossil posted a topic in Micro-paleontology
I've just got "microfossils, second edition" by Armstrong & Brasier to start my education. Additionally, I've added a AMscope 150 (got it for $4.95 plus shipping from Goodwill:)) to my AMscope 3.5-90X stereo scope - both output to a 50" HD 4K TV. I realized that I am toss left over matrix that because it is from marine environments might have micro fossils in it. The stereo scope is very good from using the .5 and standard (1) mag's, very clear on the TV using a 5 mb camera with/without stacking images. I tried the 150 yesterday and feel comfortable with the 4 and 10 x objects. The 40x objective make a single grain (pretty clear) about 12" on the screen (I've made a spread sheet that calculate the magnification for each scope and setup), not that useful. I find mention of micro fossils in this formations but only mentions, not here are the species lists. So I don't know what to look for nor do I know what the specimens should look like (thus the book to get started with education). Pittsburg Bluff is around 28-32 MY, and Keasy 34-40my (Keasy overlays the Pittsburg). Any references/resources on micro fossils in these formations? What should I be looking for in your bests guess? Here are a couple sample images: #1 is from the 150, #2 the Stereo scope. Any ideas?- 2 replies
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