Trilobite (Orygmaspis spinula) on matrix - Bull River, Cranbrook, British Columbia, Canada

This specimen features an Orygmaspis spinula trilobite measuring approximately 3 × 2.25 cm, preserved near one end of a 13.5 × 8.5 cm rock plate. Its broad, rounded head shield, narrow segmented central axis and numerous finely defined thoracic segments are clearly visible. Slender lateral spines extend backward along the sides of the thorax and cephalon. 

The yellow-tan colour of the cephalon is a good example of the "calcite wafer" preservation of trilobites from the Bull River valley. The delicate wafer is preserved for the cephalon but has broken away for the body and tail. When broken, the finer details are more visible but some of the three dimensional aspect has been lost. Any specimen with the wafer preserved is special and certainly noteworthy for rare species like this one. The colour contrast makes for an attractive display specimen when combined with the trilobite's delicate spines and strong definition of the segmented body.

The specimen comes from Upper Cambrian sediments of the McKay Group in the Bull River Valley, east of Cranbrook and Fort Steele, British Columbia, Canada. 

British Columbia fossils are illegal to sell, except under special circumstances. I represent a team that has claims on several trilobite localities in BC that have been legally grandfathered into older legislation. This allows them to legally excavate, prepare and sell fossils from these particular claims, including this specimen. Learn more about British Columbia fossils and their legal status.

For those interested in learning more about the trilobites of the McKay Group I recommend the following scientific paper: Furongian (Upper Cambrian) trilobites from the McKay Group, Bull River Valley, near Cranbrook, southeastern British Columbia, Canada (2016) by Brian D. E. Chatterton and Stacey Gibb in Palaeontographica Canadiana No 35. It is jointly published by the Canadian Society of Petroleum Geologists (now known as the Canadian Energy Geoscience Association) and the Geological Association of Canada

Fossil: Trilobite
Species: Orygmaspis spinula
Age: Upper Cambrian
Formation: McKay Group
Locality: Bull River valley, East of Cranbrook, British Columbia, Canada
Dimensions: Trilobite: 3 × 2.25 cm; plate: 13.5 × 8.5 cm