Youngblood Energy Library Display Specimens

Locality: Holzmaden, Baden-Württemberg, Germany (southeast of Stuttgart)
Geologic Range: Ordovician to present (500 million years ago to present)
Approximate Age of Specimen: 172-180 million years ago (Lower Jurassic)
Description: Crinoids (Class crinoidea) are assigned to the phylum Echinodermata, which is a group of radially symmetrical marine animals, such as the starfish, sea urchins, and brittle stars. Crinoids are commonly referred to as "sea lilies". These flower-like marine, invertebrate animals are beautifully colored and live as solitary individuals.

This species (Seirocrinus subangularis, of the family Pentacrinitidae) is characterized by a globular body enclosed by a small calyx, from which freely moving "arms" extended upward to gather the animal's food. At the bottom of the jointed, flexible stem, but missing from this specimen, was a "root-like structure" by which it was attached to the sea bottom or to plant material (Rasmussen, 1977). Specimens of this species have distally tapering stems up to 18 meters (63 feet.) long (Treatise of Invertebrate Paleontology, p. T865).

This 1-meter-long (3.5-foot) single crinoid is well preserved in fine clays and silts which eventually formed the bituminous, Poisidonia Shale. To better expose the crinoid, some of the shale around the specimen has been partially removed. Chemical alteration has replaced the original, skeletal hard parts of the fossil with pyrite. Specimens of the small pelecypoda (clam), Posidonia bronni, are present in the matrix.

Locality: La Mision, Baja California, Mexico
Geologic Range: Late Cretaceous (100-60 million years ago)
Approximate Age of Specimen: 65 million years ago
Description: This Pachydiscus Catarinae (literally, ³thick disc of Caterina²) represents a fossil of one of the last ammonite lines which met with extinction approximately 65 million years ago. As the only surviving relation of the ammonites, the chambered nautilus of today's tropical seas offer an approximate idea of how a completed ammonite may have appeared.

Specimens such as this prize example occur in the narrow interval of the Rosario Formation of La Mision, Baja California. They are found in concretionary boulders that range in size from 4 ft. in diameter to 10 ft by 8 ft by 6 ft. Unfortunately only 10% of these boulders contain ammonites and a fraction of these contain specimens approaching the quality of this specimen. The presence of the shell fragments in the concretionary matrix supports the hope that an ammonite will be found within a concretion.

As a result of the compressive stress exerted on the buried ammonite, the outermost hollow chamber (which houses the body) collapses because it lacks the buttressing walls which fortify the other chambers used for gas-liquid transfer and buoyancy regulation. It is this collapse that yields shell shards that are the telltale guide for field excavation.

Locality: northeast of Monclova, Coahuila, Mexico
Geologic Range:
Subclass Ammonoidea
Ammonite - Ordovician to Cretaceous
(500 - 63 million years ago)
Subclass Nautiloidea
Nautiloid - Cambrian to present
(600 million years ago to present)
Approximate Age of Specimens: Cretaceous (100-80 million years ago)

Description: Class Cephalopoda: Ammonites and nautiloids are four-gilled cephalopods with an external shell divided into chambers by transverse plates or septa. The animal lives in the outer-most chamber. Most fossil forms have well-developed shells, which may be external or internal, and may be coiled in various ways. These highly developed marine mollusks are represented today by the pearly nautilus, octopus, and squid. Subclass Ammonoidea (ammonites) are characterized by a thick, strongly ornamented shell that is symmetrical and coiled in a plane. It has intricate sutures with finely divided lobes and saddles. The ammonites did not survive the great extinction at the end of the Cretaceous Period, as did the nautiloids. Subclass Nautiloid (nautiloids) are characterized by a centrally located siphuncle and by a straight, curved, or coiled chambered external shell with simple sutures.

An interesting and unique aspect of this large specimen is the occurrence of the nautiloid and ammonite together, suggesting synchronous deposition and subsequent fossilization. The specimen was collected from the San Felipe Formation, which is equivalent to the upper Austin Formation of Texas. As identified by Dr. Keith Young, Professor Emeritus, University of Texas-Austin, this ammonite is probably Parapuzoisia boesei of Early Campanian Age (Upper Cretaceous).

Locality: St. Clair, Schuylkill County, Pennsylvania
Approximate age: Pennsylvanian (320 million years ago)
Description: The Pennsylvanian Period in the northeastern United States was a time of lowlands and forested swamps surrounded and often periodically covered by shallow seas. Trees, some 150 feet tall, and seed ferns were very abundant in this low swampy land. These plants were the organic material that was buried and later, because of pressure and time, commonly was altered to coal.

This 1.2-meter by 1.8-meter (4 x 6 foot) slab of fossil-bearing Llewellyn Formation comes from the Southern Anthracite Coal Fields of eastern Pennsylvania. The formation is composed of a fine-grained detrital sedimentary rock (shale) formed by the compaction of clay, silt, and (in this case) trapped plant remains. Plant fossils commonly found in the Llewellyn Formation include stems and trunks, roots, cones, seeds, and leaves. Locally there are some arthropods (insects). The leaves seen on this slab are not true ferns, which bear spore cases on the undersides of their leaves, but they are seed ferns.

Now extinct, seed ferns (Gymnosperms) were prevalent during the Carboniferous (Mississippian and Pennsylvanian 345 - 280 million years ago). Some species reached heights of 30 to 40 feet. Reproduction was by seed rather than by spore. They did not flower, and their seeds were not fully enclosed.

Neuropteris and Alethopteris are two examples of seed ferns in this fossil slab. Neuropteris has oval leaflets, which alternate on either side of the stem, and its leaves have curved veinlets. Alethopteris has long, blade-like leaflets that are wider at the base. Its mid-rib vein is also very distinctive. These ferns accumulated in the fresh-water swamps, where they were buried along with the clay and silt to eventually be transformed into coal. The plant tissue was slowly replaced by pyrite. Subsequently, with deeper burial, the pyrite was replaced by a white coating of the mineral pyrophyllite.

Locality: Southeastern Morocco or southwest Algeria
Geologic Range:
Subclass Ammonoidea
(ammonite) Devonian to Cretaceous (408-63 million years ago)
Subclass Nautiloidea
(nautiloid) Cambrian to present
600 million years ago to present
Approximate Age of Specimen: Late Devonian (375-355 million years ago)
Description: This 1.9 meter (76 inch) by 1 meter (40 inch) slab composed of former marine floor sediments contains well preserved, coiled fossils called ammonites. This ammonite (genus Manticoceras) is used globally as a time-indicator of Late Devonian rocks. The fossils are said to be "incomplete" because several of the outer chambers are missing. The straight fossils are of the Subclass Nautiloidea. Unique to this slab is the presence of both ammonites and straight nautiloids. Although it is rare to find these cephalopods together, they do occur in North Africa. Also collectors frequently extract the individual fossils specimens from such a slab.

Locality: Probably from Caverna de Santo Domingo near Santa Eulalia, Chihuahua, Mexico
Geologic Age: Unknown, but younger than the Early Cretaceous limestone making up the cave in which the crystals were found.
Description: These five, clear-to-translucent, sword-like selenite crystals range in length from 122 to 160 centimeters (4 to 4.25 feet). They were first believed to have been taken from the 100 meter-long room of the "Cave of Swords" section of the Gibralter Silver Mine near Nacia, Chihuahua, Mexico. Current belief is that they were removed from one of the "rooms" of the Caverna de Santo Domingo, located near Santa Eulalia, Chihuahua, Mexico. Both mines are situated in the 97 million year old limestones from which sulfide-ore minerals have been extracted. The selenite (CaSO4*2H2O) crystals were created as water migrated through the ore-rich, Early Cretaceous limestones, dissolving the sulfide ores and producing sulfuric acid. As water reacted with the limestone, it became saturated with calcium and sulfate resulting in the gypsum being precipitated out of solution to form the large clear to colorless selenite crystals.

Locality: Travis and Williamson Counties, Texas
Geologic Age: Lower Cretaceous (about 100 million years ago)
Description: The Cedar Park Limestone (Fredericksburg Group, Walnut Formation) is a fossiliferous limestone that interfingers with the Edwards Limestone north of Austin, Texas. The limestone contains ooids, microfossils, and finely crushed fossil debris. It is a distinctive 1.1-meter (4-ft.) thick layer of shelly limestone, which contains numerous cavities that are fossil molds of the pelecypod (clams), e.g. Trigonia and Protocardia exana. The oyster (Exogyra texana) and the gastropod (Turritella) are also common.
General Description: Used as a dimension stone in the building trade, this shelly layer is marketed as the "Cordova Shell". It has been used on interior and exterior walls of government and private buildings throughout the United States, especially in Texas. In the Youngblood Library, a 6 centimeter (2.5-inch) thick veneer has been used on the base of the circulation counter, as a frame for the crinoid, and on the walls of the hallway and entrance into the Library.

Locality: Saint-Alexis-des-Monts, Quebec, Canada
Geologic Age: Precambrian (Late Grenvillian, approximately 1.1 billion years ago)
Technical Description: A crystalline, igneous rock, the Saint-Didace massif is described (Nantel,1983) as predominately quartz monzonite and granite, but floor and counter materials are actually closer to quartz syenite containing approximately 15% quartz, 55% alkali-feldspar, 20% plagioclase feldspar, and 10% hornblende and biotite. The brownish color is imparted by 2-to-5 centimeter tabular to ovoid phenocrysts, sometimes rimmed by white plagioclase (Rapakivi texture). The rock is sharply porphyritic (potassium feldspar megacrysts in fine-grained quartz-plagioclase-hornblende-biotite groundmass), and generally lacks a strong foliation or lineation. Locally high concentrations of mafic minerals (hornblende plus biotite) in clots and irregular patches may represent partially assimilated fragments (xenoliths) of the surrounding country rocks.
General Description: The stone was quarried about halfway between Montreal and Quebec City from within the 77-square-kilometer (30-square-mile) Saint-Didace massif of the Grenville tectonic province. As a dimension stone, it is marketed as the "Autumn Brown Granite" or "Newton Granite."

Locality: Southwestern Wyoming, USA, probably from the Fossil Basin
Geologic Range: Eocene Epoch (55-34 million years ago)
Approximate Age of Specimen: 50 million years old
Description: Near the end of the Paleocene Epoch or beginning of the Eocene Epoch (60 to 45 million years ago), the Green River Lake System was formed in Wyoming, eastern Utah, and northwestern Colorado. This system consisted of three mostly freshwater lakes: Lake Uinta, Lake Gosiute, and Fossil Lake. This 245 cm (8 ft) tall by 181 (6 ft) wide slab, which contains a large palm frond and a herringlike fish, probably came from Fossil Lake. Fossil Lake lasted about 2 million years and, at 50 miles wide at its maximum, was the smallest of the three freshwater lakes. Thousands of other fossils, including more than 20 species of fish, have been recovered from the ancient bed of Fossil Lake.

The Eocene climate of the Fossil Lake area was subtropical, much like today's climate along the U.S. coast of the Gulf of Mexico. Palms, figs, cypress, and other semi-tropical plants thrived in the lowland valleys. Seasonal rainy periods may have induced frequent carbonate precipitations. The layers that formed from precipitated carbonate mud provided a protective cover for the bodies of fish and plants that had died and fallen to the bottom, and may have also contributed to the exquisite fossilization of the almost 188cm (6 ft) tall by 4 1/2 ft wide sabal palm (Sbalites sp.) frond that dominates this slab.

Nearly three hundred feet of mainly laminated micrite (microcrystalline carbonate rock) filled Fossil Lake and are exposed today as the Green River Formation. Although fossil specimens can be found throughout the widespread Green River Formation, most of the specimens collected are from the middle and upper parts of the formation. In locations beyond Fossil Lake, the shales of the Green River Formation are well known as "oil shales" because they hold waxy hydrocarbons called kerogen.
Diplomystus dentatus: The 22cm (9 inch) fish is commonly identified in Fossil Lake and was the largest herring genus. It can be distinguished by the presence and pattern of scale rows, or scutes, that lie along the midline of the back from the skull to the dorsal fin. The deep-bodied form and elongate anal fin are easily recognizable characteristics. The body form and the upturned mouth suggests that the fish fed on smaller surface-dwelling fish and/or insects.