JOHN DAY FOSSIL BEDS

More than a 100 groups of mammals and a wide variety of plants have been found in the early Miocene, 39-19 million year old, John Day Formation near Kimberly, Oregon. The fossiliferous strata that have yielded beautifully preserved specimens of many of the animals we see domesticated today.

Dogs, cats, swine and horses are common. Oreodonts, camels, rhinoceros and rodents have also been found in this ancient deciduous forested area.

Here my talented young paleontologist cousin Spencer is holding a well preserved Oreodont skull.Many sites in Oregon yield beautifully preserved fossil shells laid down over 60 million years.
The asteroid that hit the Gulf of Mexico at the end of the Cretaceous caused a seafloor rift that split ancient Oregon. The massive hole left behind as the coastal lands slid northward filled in with sediment, refilling the basin.

These marine sediments were uplifted around the time of the birth of Oregon's Coastal Range. Easily collected and identified, as they look very similar to their modern cousins, you can dig for marine fossils all along Oregon's beachfront. I'll post some photos when I return from collecting later this year.

DEWDROPS

MUMMIFIED BRANCHIOSTEGUS

An amazing mummified tilefish, Branchiostegus japonicus (Houttuyn, 1782) from Holocene deposits near Shizuoka, Japan. This specimen shows remarkable detail right down to the scales. Quite spectacular, truly.

Modern cousins of this fellow live as far south as the Arafura Sea today. Collection and photos from the deeply awesome Takashi Ito. サンさん、ありがとうございました

DEEPLY GROOVED DECAPOD

A beautiful example of the "deeply groovy" decapod, Dorippe sinica, from Holocene deposits near Shizuoka, Japan. This regal fellow has a strongly sculptured carapace. He looks like he would have been quite the bruiser moving about on the seafloor looking for tasty snacks. He likely enjoyed just about any form of meat, potentially dining on fish, worms, eggs, squid, starfish or even a few of his slow-moving cousins.

The carapace is deeply grooved with conspicuous wart-like tubercles; anterolateral margin, between the base of the exorbital tooth and cervical groove, smooth, without tubercles or denticles.

The teeth on the lower orbital margin in the cluster. Carpus of cheliped distinctly granulated on the upper surface and with a conspicuous row of granules along the anterior margin. Though missing here, the merus of second and third pereiopods are almost cylindrical. (Türkay 1995). This specimen was collected and is the collection of the deeply awesome Takashi Ito of Japan

FRENCHMAN MOUNTAIN TRILOBITE: BRISTOLIA INSOLENS

Bristolia insolens

A stunning Cambrian trilobite, Bristolia insolens, from Frenchman Mountain near Las Vegas, Nevada.

The mountain provides an example of the Great unconformity with the tilted Paleozoic Tapeats Sandstone underlain by Paleoproterozoic Vishnu Schist. An unconformity is a buried erosional or non-depositional surface separating two strata of different ages. We know when we find these that the sediment was not laid down in a continuous deposition. The range also boasts some of the oldest rock on the North American continent, at about two billion years old.

This spectacular specimen is in the collection of York Yuxi Wang. It is about 4-5cm long; 3-4cm wide.

PADDLING WITH THE PUPPERS

MOLLUSCA GASTROPODA

Gastropods, or univalves, are the largest and most successful class of molluscs. They started as exclusively marine but have adapted well and now their rank spend more time in freshwater than in salty marine environments.

Many are marine, but two thirds off all living species live in freshwater or on land. Their entry into the fossil record goes all the way back to the Cambrian.

Slugs and snails, abalones, limpets, cowries, conches, top shells, whelks, and sea slugs are all gastropods. They are the second largest class of animals with over 60,000–75,000 known living species.

The gastropods are originally sea-floor predators, though they have evolved to live happily in many other habitats. Many lines living today evolved in the Mesozoic. The first gastropods were exclusively marine and appeared in the Upper Cambrian (Chippewaella, Strepsodiscus).

By the Ordovician, gastropods were a varied group present in a variety of aquatic habitats. Commonly, fossil gastropods from the rocks of the early Palaeozoic era are too poorly preserved for accurate identification. Still, the Silurian genus Poleumita contains fifteen identified species.

Most of the gastropods of the Palaeozoic era belong to primitive groups, a few of which still survive today. By the Carboniferous period many of the shapes we see in living gastropods can be matched in the fossil record, but despite these similarities in appearance the majority of these older forms are not directly related to living forms. It was during the Mesozoic era that the ancestors of many of the living gastropods evolved.

In rocks of the Mesozoic era gastropods are more common as fossils and their shell often very well preserved. While not all gastropods have shells, the ones that do fossilize more easily and consequently, we know a lot more about them. We find them in fossil beds from both freshwater and marine environments, in ancient building materials and as modern guests of our gardens.

ARTHROPODA TRILOBITA

IDENTIFYING FOSSIL BONE

If you’re wondering if you have Fossil Bone, you’ll want to look for the telltale texture on the surface. It’s best to take the specimen outside and photograph it in natural light.

With fossil bone, you will be able to see the different canals and webbed structure of the bone, sure signs that the object was of biological origin.

As my good friend Mike Boyd notes, without going into the distinction between dermal bone and endochondral bone —  which relates to how they form - or ossify — it's worth noting that bones such as the one illustrated here will usually have a layer of smooth — periosteal — bone on the outer surface and spongy — or trabecular — bone inside.

The distinction can be well seen in the photograph. The partial weathering away of the smooth external bone has resulted in the exposure of the spongy bone interiors. Geographic context is important, so knowing where it was found is very helpful for an ID. Knowing the geologic context of your find can help you to figure out if you've perhaps found a terrestrial or marine fossil. Did you find any other fossils nearby? Can you see pieces of fossil shells or remnants of fossil leaves? Things get tricky with erratics. That's when something has deposited a rock or fossil far from the place it originated. We see this with glaciers. The ice can act like a plow, lifting up and pushing a rock to a new location, then melting away to leave something out of context.

ZEACRINITES MAGNOLIAEFORMIS

This lovely specimen is Zeacrinites magnoliaeformis, an Upper Mississippian-Chesterian crinoid found by Keith Metts in the Glen Dean Formation, Grayson County, Kentucky, USA.

Crinoids are unusually beautiful and graceful members of the phylum Echinodermata. They resemble an underwater flower swaying in an ocean current. But make no mistake they are marine animals. Picture a flower with mouth on the top surface that is surrounded by feeding arms. Awkwardly, add an anus right beside that mouth. That's him!

Crinoids with root-like anchors are called Sea Lilies. They have graceful stalks that grip the ocean floor. Those in deeper water have longish stalks up to 3.3 ft or a meter in length.

Then there are other varieties with that are free-swimming with only vestigial stalks. They make up the majority of this group and are commonly known as feather stars or comatulids.

Unlike the sea lilies the feather stars can move about on tiny hook like structures called cirri. It is this same cirri that allows crinoids to latch to surfaces on the sea floor.

Like other echinoderms, crinoids have pentaradial symmetry. The aboral surface of the body is studded with plates of calcium carbonate, forming an endoskeleton similar to that in starfish and sea urchins.

These make the calyx somewhat cup-shaped, and there are few, if any, ossicles in the oral (upper) surface called a tegmen. It is divided into five ambulacral areas, including a deep groove from which the tube feet project, and five interambulacral areas between them. The anus, unusually for echinoderms, is found on the same surface as the mouth, at the edge of the tegmen.

Crinoids are alive and well today. They are also some of the oldest fossils on the planet. We have lovely fossil specimens dating back to the Ordovician.

CROCODILIAN UPSTARTS: THE CRUROTARSANS

Dinosaurs, long hailed as the rulers of the Triassic almost lost the title belt to a group of crocodilian upstarts, the crurotarsans. In a short-lived battle for survival, geologically speaking, the two groups ran head-to-head for about thirty million years.

The Crurotarsi or "cross-ankles" as they are affectionately known, are a group of archosaurs - formerly known as Pseudosuchians when paleontologist Paul Serono, the darling of National Geographic, renamed them for their node-based clade in 1991. Image: By Nobu Tamura (http://spinops.blogspot.com) - Own work, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=19459679

HEXACORALLIA

Hexacorallia is a subclass of Anthozoa comprising approximately 4,300 species of aquatic organisms formed of polyps, generally with six-fold symmetry. Their temporal range is from the Fortunian to the Holocene. The subclass includes all of the stony corals, most of which are colonial and reef-forming, as well as all sea anemones, and zoanthids, arranged within five extant orders.

The hexacorallia are distinguished from another subclass of Anthozoa, Octocorallia, in having six or fewer axes of symmetry in their body structure; the tentacles are simple and unbranched and normally number more than eight. These organisms are formed of individual soft polyps which in some species live in colonies and can secrete a calcite skeleton. As with all Cnidarians, these organisms have a complex life cycle including a motile planktonic phase and a later characteristic sessile phase. Hexacorallia also includes the significant extinct order of rugose corals.

AURELIA AURITA: MOON DANCERS

Moon Jelly Fish / Aurelia Aurita

Aurelia aurita (also called the common jellyfish, moon jellyfish, moon jelly or saucer jelly) is a widely studied species of the genus, Aurelia. All species in the genus are closely related, and it is difficult to identify Aurelia medusae without genetic sampling; most of what follows applies equally to all species of the genus.

The genus Aurelia is found throughout most of the world's oceans, from the tropics to as far north as latitude 70° north and as far south as 40° south. The species Aurelia aurita is found along the eastern Atlantic coast of Northern Europe and the western Atlantic coast of North America in New England and Eastern Canada. In general, Aurelia is an inshore genus that can be found in estuaries and harbours.

The genus Aurelia is found throughout most of the world's oceans, from the tropics to as far north as latitude 70° north and as far south as 40° south. The species Aurelia aurita is found along the eastern Atlantic coast of Northern Europe and the western Atlantic coast of North America in New England and Eastern Canada. In general, Aurelia is an inshore genus that can be found in estuaries and harbours.