Trilobites of the Eager Formation:

 

Eager Formation, Lower Cambrian, Cranbrook area, B. C.

 

Trilobites:

 

Bonnaspis fieldensis (Walcott, 1916b)

Bonnia "drysdalia" (Bohach, 1997 unpubl. thesis)

Bonnia "fritzi" (Bohach, 1997 unpubl. thesis)

Bonnia "grandis" (Bohach, 1997 unpubl. thesis)

Bonnia lateraspina Fritz, 1972

Bonnia "ornata" (Bohach, 1997 unpubl. thesis)

Bonnia sp. 1 (Bohach, 1997 unpubl. thesis)

Elliptocephala "parentalis" (Bohach, 1997 unpubl. thesis)

Fremontella "ashtoni" (Bohach, 1997 unpubl. thesis)

Fremontella "campbellae" (Bohach, 1997 unpubl. thesis)

Mesonacis eagerensis (Best, 1952)

Mesonacis "graingerensis" (Bohach, 1997 unpubl. thesis)

aff. Mesonacis leechi n. sp. " (Bohach, 1997 unpubl. thesis)

Olenellus gilberti sensu Best, 1952 = Olenellus schucherti

Olenellus "ricei" (Bohach, 1997 unpubl. thesis)

Olenellus schofeldi Best

Olenellus schucherti Resser and Howell, 1938

Olenellus transitans (Walcott, 1910b)

Olenellus sp.

Paedeumias sp. (not sure if this is correctly identified)

Proliostracus buelnaensis (Lochman, 1952)

Proliostracus sp. (Bohach, 1997 unpubl. thesis)

Wanneria "dunnai" (Bohach, 1997 unpubl. thesis)

Wanneria logani (Walcott, 1910b)

Wanneria "watsonensis" (Bohach, 1997 unpubl. thesis)

Wanneria n. sp.

wanneriid sp. (Bohach, 1997 unpubl. thesis)

Wenkchmnia? sp. 1 (Bohach, 1997 unpubl. thesis)

Rare ptychopariids

Rare corynexochids

 

Comments:

 

    Many of the trilobite species listed here are from an unpublished thesis (Bohach, 1997) and are listed in "quotes". The identity of O. schucherti, O. schofieldi, Paedeumias sp. and Wanneria n. sp. are uncertain and need comparison with the species listed in Bohach (1997). The Olenellus are likely O. "ricei" and the Wanneria is likely W. "dunnae". Since the work is still as yet unpublished, the species identifications are tentative.

    The Eager Formation is underlain by the Cranbrook Formation and overlain by the Jubilee Formation. There are 3 subzones within the Eager (oldest to youngest): Wanneria logani, Wanneria dunnae, and Proliostracus buelnaensis subzones.

    The Lower Cambrian Eager Formation, near Cranbrook and Fort Steele, B. C., contain many complete specimens and fragments of olenellid trilobites in grey and brown shales. The most abundant is Olenellus, which has a large, semi-circular head, a body of 15 segments, a long spine on the 15th segment, and a minute tail. Wanneria is less common and has a large head lacking conspicuous furrows, and a broad body without an expanded third segment. The shales of the Eager Formation are exposed in the Kootenay and Columbia river valleys, but the most fossiliferous site is located on Crown Lands leased to the Cranbrook Rifle Club, located just outside of Fort Steele. Lisa Bohach (unpubl. Ph.D. thesis 1997) established a new classification of olenellid trilobites based on the different growth history (ontogeny) of major groups.    

 

References:

 

Bohach, Lisa. 1997. Systematics and biostratigraphy of Lower Cambrian trilobites of western Laurentia. Unpublished Ph.D. thesis, University of Victoria, 491 p., 41 pls.

 

Spencer, J. and Chatterton, B. D. E. (1997)  Second International Trilobite Conference, Field trip 2 Excusion Guidebook. Trip to the Canadian Rocky Mountains, Aug. 15 20, 1997.

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