A new tissue-grade organism 1.5 billion years old from Montana

"Problematic bedding-plane markings" that resemble a "string of beads" from the Appekunny Formation in the eastern part of Glacier National Park Monta na are described as Horodyskia moniliformis, a new genus and new species. T he matrix shows laminations at an exceptionally fine scale, and, during lif e these aquatic organisms may have been intermittently lightly covered by w ind-blown quartz dust. Growth stages are present: tiny, elongate, benthonic threads develop swellings; swellings grow upward; more robust forms have w ide short cones. At all growth stages, the spacing of the cones is approxim ately proportionally to the diameter of the enlarging cones. To account for this phenomenon, presumably cones intermediate in position along the threa d episodically ceased growth. Thus, the organism exhibits a form of colonia l growth.