Discover and read the best of Twitter Threads about #sundanceformation
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Like most people, my absolute favourite western North American sequence of Middle Jurassic to Upper Jurassic age marine shale, sandy shale, sandstone & limestone has always been the Sundance Formation - & today I will get to tramp an entire stretch of it! #JurassicWyoming
Woohoo - Jurassic oysters! #SundanceFormation 
Woohoo - the internal skeleton of a belemnite! #SundanceFormation
