Natural History
The Brule Formation is a sequence of fine grained clastic rocks (claystones, mudstones, siltstones) interbedded with freshwater carbonates, volcanic ash (tuff), and sandstonein South Dakota, Nebraska, Colorado, North Dakota, and Wyoming. It was deposited between 34 and 30 million years ago, roughly the Rupelian age (Oligocene). It occurs as a subunit of the White River Group.
Illustrations of the Family of Psittacidae, or Parrots.
Environment Protection and Biodiversity Conservation Act 1999.
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