Knowledge Bank

An association of ammonites and conodonts was discovered concentrated in thin lenticular limestone beds interbedded with siltstones in the Lower Triassic Thaynes Formation in northeastern Nevada. The mere presence of the limestone within the siltstones is due to current accumulations of shell material and fragments. After considering the various aspects of possible paleobiological relationships (i.e., commensalism, mutualism, parasitism, predation, post mortum relationships, etc.), and examining the distribution and ratios of the elements of multielement and single element conodont apparatuses, it is believed that the ammonite-conodont association results from the same factors which account for the limestone facies, that is, current accumulations of ammonite conchs and conodont elements.