Cambrian

Cambrian: the beginning of the Paleozoic Era.

Animals with hard-shells appeared in great numbers for the first time during the Cambrian. The continents were flooded by shallow seas. The supercontinent of Gondwana had just formed and was located near the South Pole.

More Info about the Cambrian      

 Panotia, the supercontinent that formed at the end of the Precambrian Era, approximately 600 million      

 years ago, had already begun to break apart by the beginning of the Paleozoic Era. A new ocean, the Iapetus      

 Ocean, widened between the ancient continents of Laurentia (North America), Baltica (Northern Europe), and      

 Siberia.  Gondwana, the supercontinent that was assembled during the Pan-African orogeny, was the largest       

continent at this time, stretching from the Equator to the South Pole.      

   During the Ordovician Period, warm water deposits, such as limestones and salt, were found in the equatorial      

 regions of Gondwana (Australia, India, China, and Antarctica), while glacial deposits and ice-rafted debris occurred      

 in the south polar areas of Gondwana (Africa and South America).