It is most common in deep-water sediments, but is a constituent of most Ediacaran fossil assemblages, including those deposited above storm wave-base.

Even so, his findings were questioned by Charles Doolittle Walcott, who quoted opinion that the shapes in the rocks were concretions formed inorganically.

[9] Other explanations offered at the time were that the circles were gas escape bubbles, or fakes planted by God to lure those with little faith into error[citation needed].

[10] Fossils were found in many other parts of the world in rocks of about the same age and became accepted as genuine remains of life forms.

For example, Spriggia and Ediacaria appear to be remains of the same animals, only that the former was fossilized in more compact, fine-grained clay, whereas the latter is known from rocks that originally were predominantly sandy sediment.

Thus, if Aspidella in the loose sense turns out to be an assemblage of more or less related taxa, the genus name would apply only to the smallish ellipsoid specimens.

[11] Other locations where Aspidella specimens are reported include the Bonavista Peninsula and Mistaken Point in Newfoundland, the Twitya Formation in British Columbia, and central North Carolina.

[13] More recently, Aspidella fossils have been found in the mid-Tonian-aged Heavitree Formation, Amadeus Basin, Central Australia, dated to ~ 850 million years ago.