1921 passport photograph of Ruth F. Gillespie (restored in Adobe Photoshop) I live near outcrops of the Ordovician Period Bardstown Reef f...

  Here is an alga fossil called  Thalassocystis striata  (Taggart & Parker, 1976). It existed in the Silurian Period (443-417 million ye...

  Here is an alga fossil called  Buthotrephis sp.  (Hall, 1847). It existed in the Silurian Period (443-417 million years ago). The fossil w...