Fig. 1
Introducing Late Cambrian Cryptozoon Hall 1884. (A) Summary of reports of Neoproterozoic to Phanerozoic carbonate rock microfabrics interpreted as non-spiculate (essentially keratosan) sponges; relative frequency of reports redrawn from5. Asterisk indicates the age of our test case, topotype Cryptozoon Hall 1884. (B) Stratigraphic section (Late Cambrian, Lester Park, Greenfield Township, Saratoga County, New York State, 43° 05′ 28′′ N, 73° 50′ 53′′ W)15. Cryptozoon formed under marginal-marine conditions correlated with highstand system tracts. Lower part of section contains the morphospecies C. proliferum; upper part contains C. ruedemanni and C. undulatum59. (C) Disconformity marked by quartz sand layer on beveled surface of C. proliferum. (D) Scan of thin section of C. proliferum (hypotype NYSM 19,458.1) displaying three kinds of primary laminae-layers: densely-clotted pelletoidal micrite with microbial filaments (F), locally tufted; loosely-clotted pelletoidal micrite with vesicular microfabric (V), and dense microcrystalline laminae (M). A fourth, stratiform to patchy fabric (AL) represents suspect sponges4. However, these domains cross-cut the primary layering and contain relic structures (asterisks) indicating recrystallisation or neomorphism. Note finger-like protrusions of AL domains. There are peculiar traces (t) of possible biogenic origin (recrystallized, no relic structures).
