Nj. Butterfield et Cj. Nicholas, BURGESS SHALE-TYPE PRESERVATION OF BOTH NON-MINERALIZING AND SHELLY CAMBRIAN ORGANISMS FROM THE MACKENZIE MOUNTAINS, NORTHWESTERN CANADA, Journal of paleontology, 70(6), 1996, pp. 893-899
Lower to Middle Cambrian shales of the Mount Cap Formation in the Mack
enzie Mountains, northwestern Canada, host a variety of Burgess Shale-
type macrofossils, including anomalocarid claws, several taxa of bival
ved arthropod, articulated hyolithids, and articulated chancelloriids.
Hydrofluoric acid processing has also yielded a broad range of organi
c-walled fossils, most of which are derived from forms more typically
known as shelly fossils; e.g., trilobites, inarticulate brachiopods, s
mall shelly fossils (SSF), hyolithids, and chancelloriids. Organic-wal
led hyolithids include conchs, opercula and helens; the proximal artic
ulation of the helens is erosive, suggesting that they were formed ''i
nstantaneously'' and periodically replaced. Organic-walled chancellori
id sclerites exhibit a polygonal surface texture and an inner ''pith''
of dark granular material with distally oriented conoidal divisions;
such a pattern is similar to that seen in the fibers of some modern ho
rny sponges and points to a poriferan relationship for the chancellori
ids. The robust nature but minimal relief of most of these fossils sug
gests that primary biomineralization was minimal.