"Cyanobacterial Activity"
Stromatolites & Thrombolites
The strata exposed in these excavations belong to the Pittsford
Member of the Silurian Vernon Formation and are rarely seen.
There are no natural outcrops of these rocks. The pit in
center/foreground is Pittsford D and is overlain by a very resistant,
hard fine-grained dolostone (waterlime) termed Pittsford E. Just
past this pit is a gray lumpy area. This lumpy area and the stack of
rocks in the pit belong to Pittsford E and are interpreted herein to
represent a small 'algal' mound complex. I interpret these forms to
be due to the activity of microbes--the bed is a microbial carbonate
that thickens and thins (about 1 - 10 cm.).
Within this unit, eurypterid remains are preserved in 3D - but are
very difficult to extricate. A large collection of material from this
bed was obtained only because of access to this unit over a period
of over 6 months. Specimens of the fauna retrieved from Pittsford
E will be illustrated on other pages within this website. The rock is
so hard and difficult to split that a hand sledge had to be utilized.
Spring House Commons Site
Microbial Carbonates
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