Multiple trilobite fragments fossilized in the same rock
USNM_35225 and USNM_35227: Pictured are multiple trilobite fragments fossilized in the same rock. These are commonly known as hash beds. "Hash" is an indicator of a near-shore environment, where waves could hav... More
Multiple trilobite fragments fossilized in the same rock
USNM_35227 (pictured) and USNM_35225: Multiple trilobite fragments are fossilized in the same rock, these are commonly known as hash beds. "Hash" is an indicator of a near-shore environment, where waves could h... More
Yellowstone National Park, Agnostid trilobite
YELL-165705: A small, Agnostid trilobite (YELL-165705) head is shown here. How did these little arthropods survive 500 million years ago? From their lack of eyes and poorly suited swimming body, scientists infe... More
Trilobite Ehmania walcotti, Yellowstone National Park
USNM_90667: During the Cambrian period and throughout the Paleozoic era, an inland sea occupied the Greater Yellowstone area, unlike its present landscape of mountains, geysers, and rivers. Fossils, like this t... More
Yellowstone National Park, Ptychopariid trilobite
YELL-165706 (pictured) and YELL-165715: Many times when fossils are collected they are only casts of the specimen, such as these pictures of a few nearly complete Ptychopariid trilobite (YELL-165706 and YELL-16... More
Yellowstone National Park, Ptychopariid trilobite
YELL-165706 and YELL-165715 (pictured here): Many times when fossils are collected they are only casts of the specimen, such as the pictures above of a few nearly complete Ptychopariid trilobite (YELL-165706 an... More
Yellowstone National Park, Ptychopariid trilobite
YELL-92020: This head of a roughly 520 million year old Ptychopariid trilobite (YELL-92020) is one among many identified from the Pilgrim Limestone, on Mt. Holmes in Yellowstone National Park. Trilobite order P... More
Multiple trilobite fragments fossilized in the same rock
USNM_35236: Charles D. Walcott, renowned invertebrate paleontologists, identified trilobite specimen Solenopleura? weedi (USNM 35236) from the Upper Cambrian (~500 million years ago) Pilgrim limestone in northw... More
Multiple trilobite fragments fossilized in the same rock
USNM_61523: Dated about 500 million years old and collected from the Pilgrim Limestone in Yellowstone National Park, is type trilobite Tricrepicephalus yellowstonensis (USNM 61523). This particular species is j... More
trilobite Blountia polita, Yellowstone National Park
USNM_96488: The trilobite Blountia polita (USNM 96488) (pictured) was discovered in the Middle Cambrian (~520 million years ago), Pilgrim Formation of Yellowstone National Park. As trilobites continued to evolv... More