8,153 research outputs found

    Sespe Eocene didelphids

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    In segregating a number of tiny insectivore and primate jaws from the Sespe deposits of California, several specimens were noted that clearly belong to marsupials. These are all incomplete but possess interest because they record didelphids for the first time in the North American upper Eocene and secondly because this group of mammals has not been known heretofore in Tertiary faunas west of the Rocky Mountains except for a single occurrence in the upper Oligocene John Day assemblage of north-central Oregon

    A Neocene Erosion Surface in Central Oregon

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    A landscape, in the old age stage, termed the Ochoco Erosion Surface, bevels the Columbia lavas and Mascall formation of middle Miocene age at a large angle, and the Rattlesnake lower or middle Pliocene at a small angle, in parts of the Ochoco Range and the John Day country of central Oregon. North of the John Day country the Condon Erosion Surface, locally at least a peneplane, probably but at present not demonstrably the correlative of the Ochoco, truncates the Columbia lavas and perhaps The Dalles formation. A pause in the eventful diastrophic history of this part of the Northwest is apparently indicated by these features. Subsequently, during the present or Dayville cycle, the great gorges and valleys have been excavated

    Stratigraphy and petrography of the Selah member of the Ellensburg formation in south-central Washington and north-central Oregon

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    The Ellensburg Formation of south-central Washington and north-central Oregon has been described by many workers from the time of the original description by Russell (1893) to recent work by Schmincke (1964). However, detailed information concerning the stratigraphy and petrography of the Ellensburg Formation in south-central Washington and north-central Oregon is not available. This study is among the first detailed studies made for a member of the Ellensburg Formation; it provides a specific comparison with the type Ellensburg of central Washington

    MAARS OF SOUTH-CENTRAL OREGON By

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    If we could go back in time some 5 to 10 million years to the Pliocene Epoch and recreate the landscape of south-central Oregon, here are some of the things we would probably see: From a plain originally of slight relief, faulting has already delineate

    A Neocene Erosion Surface in Central Oregon

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    A landscape, in the old age stage, termed the Ochoco Erosion Surface, bevels the Columbia lavas and Mascall formation of middle Miocene age at a large angle, and the Rattlesnake lower or middle Pliocene at a small angle, in parts of the Ochoco Range and the John Day country of central Oregon. North of the John Day country the Condon Erosion Surface, locally at least a peneplane, probably but at present not demonstrably the correlative of the Ochoco, truncates the Columbia lavas and perhaps The Dalles formation. A pause in the eventful diastrophic history of this part of the Northwest is apparently indicated by these features. Subsequently, during the present or Dayville cycle, the great gorges and valleys have been excavated

    Comparative Rates of Western Juniper Afforestation in South-Central Oregon and the Role of Anthropogenic Disturbance

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    We examine changes in canopy cover for adult western juniper from the 1960s to 1994 in central Oregon using repeat aerial photography. We compare changes at four sites with a land-use history of minimal anthropogenic disturbance to changes on adjacent sites that have a disturbance history more typical of central Oregon rangelands. Canopy cover increased at all sites, but afforestation on sites with domestic livestock grazing was greater. The potential driving forces common to all sites include a long fire-free interval, early twentieth-century favorable climatic conditions, biological inertia, and atmospheric CO2 enrichment

    Regional Action Initiative: Engaging Oregonians in a New Level of Civic Leadership 2008-2013

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    The OCF board of directors launched the Regional Action Initiative (RAI) in 2008 to engage Oregonians in a new level of civic leadership and empower them to improve lives in their regions. To support the Initiative, the board provided a special one-time allocation of 1milliontoeachofOCF′sserviceregions,includingCentralOregon,EasternOregon,MetropolitanPortland,NorthernWillametteValley,SouthernOregon,SouthernWillametteValleyandtheCoast.TheCoastregionsplittheir1 million to each of OCF's service regions, including Central Oregon, Eastern Oregon, Metropolitan Portland, Northern Willamette Valley, Southern Oregon, Southern Willamette Valley and the Coast. The Coast region split their 1M allocation between the North and South. Each of the eight OCF regional volunteer Leadership Councils led a process to investigate the needs of their communities, identify a focus area, engage community members and fund successful strategies for change. The results from this five-year Initiative are included in this summar

    Diel variation in vertical distribution of an offshore ichthyoplankton community off the Oregon coast

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    We examined the diel ver-tical distribution, concentration, and community structure of ichthyoplank-ton from a single station 69 km off the central Oregon coast in the northeast Pacific Ocean. The 74 depth-stratified samples yielded 1571 fish larvae from 20 taxa, representing 11 families, and 128 fish eggs from 11 taxa within nine families. Dominant larval taxa were Sebastes spp. (rockfishes), Stenobra-chius leucopsarus (northern lampfish), Tarletonbeania crenularis (blue lan-ternfish), and Lyopsetta exilis (slender sole), and the dominant egg taxa were Sardinops sagax (Pacific sardine), Icichthys lockingtoni (medusafish), and Chauliodus macouni (Pacific viperfish). Larval concentrations generally increased from the surface to 50 m, then decreased with depth. Larval concentrations were higher at night than during the day, and there was evidence of larval diel vertical migration. Depth stratum was the most important factor explaining variability in larval and egg concentrations
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