Trigonia
Species
Trigonia americana Meek, 1873
Occurrence: Piper (middle), Carmel; Sliderock, Rich, and Leeds Creek Members of Twin Creek Limestone
Reference: Imlay, 1964; Imlay, 1967
![Specimen Photo](TrigoniaAmericanaImlay.jpg)
Trigonia americana
Photograph from Imlay, 1964
Trigonia elegantissima Meek, 1873
Distinguished from T. americana by being less erect, much smaller, morely finely and densely ribbed
Occurrence: Carmel; Sliderock, Rich, Boundary Ridge, Watton Canyon, and Leeds Creek Members of Twin Creek Limestone
Reference: Imlay, 1964; Imlay, 1967
![Specimen Photo](TrigoniaElegantissimaImlay.jpg)
Trigonia elegantissima
Photograph from Imlay, 1964