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    Description

    POSITIVE AND NEGATIVE FISH FOSSIL
    Tharsis dubius
    Jurassic
    Solnhofen Formation, Eichstätt, Bavaria, Germany

    It takes very rare and special conditions to preserve a specimen like this in both positive and negative forms. First the dead creature must be covered by sediment very quickly, usually at the bottom of a body of water, and then this sediment must harden to form a nodule wholly enclosing the animal but remaining distinct from the sedimentary layers building up around it. Once the organic material has decayed away, the cavity is filled with some other mineral - calcite, siderite or similar - but retaining both positive and negative impressions. This is not dissimilar to the way all fossils are formed, but if the nodule does indeed remain distinct from the rock that forms around it, then once removed whole it can be split along the naturally weaker plane on which the original creature lay to expose two mirror images as here; the positive and negative record of a 150 million year-old fish. Such specimens are, of course, rare and highly sought-after, and this example preserves the remains of a slender, curving Tharsis, a schooling fish common to the region. Both halves boast superb three-dimensionality; from the large bony head, to detailed individual vertebrae, to textured slim forked tail fins. Measuring 8½ inches around the curve of the body, each sits in an irregularly shaped limestone matrix measuring approximately 18 x 19½ inches. The matrix is beautifully decorated with the natural fern-like dendrites; patterning caused by iron-rich water seepage.


    Condition Report*: Condition report available upon request.
    *Heritage Auctions strives to provide as much information as possible but encourages in-person inspection by bidders. Statements regarding the condition of objects are only for general guidance and should not be relied upon as complete statements of fact, and do not constitute a representation, warranty or assumption of liability by Heritage. Some condition issues may not be noted in the condition report but are apparent in the provided photos which are considered part of the condition report. Please note that we do not de-frame lots estimated at $1,000 or less and may not be able to provide additional details for lots valued under $500. All lots are sold "AS IS" under the Terms & Conditions of Auction.

    Auction Info

    Auction Dates
    June, 2011
    12th Sunday
    Bids + Registered Phone Bidders: 2
    Lot Tracking Activity: N/A
    Page Views: 1,052

    Buyer's Premium per Lot:
    19.5% of the successful bid (minimum $14) per lot.

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