<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:creator>Douglas J. Nichols</dc:creator>
  <dc:date>2002</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;The&amp;nbsp;&lt;/span&gt;Hell&lt;span&gt;&amp;nbsp;&lt;/span&gt;Creek&lt;span&gt;&amp;nbsp;&lt;/span&gt;Formation&lt;span&gt;&amp;nbsp;of&amp;nbsp;&lt;/span&gt;North&lt;span&gt;&amp;nbsp;&lt;/span&gt;Dakota&lt;span&gt;&amp;nbsp;preserves a rich and varied palynoflora including pollen, spores, and algal cysts; this palynoflora provides insight into the nature of plant life&amp;nbsp;&lt;/span&gt;in&lt;span&gt;&amp;nbsp;the region&amp;nbsp;&lt;/span&gt;in&lt;span&gt;&amp;nbsp;late Maastrichtian time. This palynological record supplements extensive data from the same ancient vegetation preserved&amp;nbsp;&lt;/span&gt;in&lt;span&gt;&amp;nbsp;the megafloral record, and it provides background biostratigraphic data necessary to determine the nature of the Cretaceous-Tertiary (K-T) boundary event. This study of the&amp;nbsp;&lt;/span&gt;Hell&lt;span&gt;&amp;nbsp;&lt;/span&gt;Creek&lt;span&gt;&amp;nbsp;palynoflora is based upon occurrences of palynomorphs&amp;nbsp;&lt;/span&gt;in&lt;span&gt;&amp;nbsp;71 samples from 20 measured sections&amp;nbsp;&lt;/span&gt;in&lt;span&gt;&amp;nbsp;Bowman and Slope Counties, southwestern&amp;nbsp;&lt;/span&gt;North&lt;span&gt;&amp;nbsp;&lt;/span&gt;Dakota&lt;span&gt;. The palynoflora documented includes 115 or more palynomorph species, 98 of which are described. Three new genera are proposed, three new species are described, and five new nomenclatural combinations are made. The new taxa are Palaeoisoetes gen. nov., Styxpollenites gen. nov., Tschudypollis gen. nov., Aquilapollenites marmarthensis sp. nov., Osmundacidites stanleyi sp. nov., Styxpollenites calamitas sp. nov., Polyatriopollenites levis (Stanley 1965) comb. nov., Palaeoisoetes subengelmannii (Elsik 1968) comb. nov., Triporopollenites triplicatus (Anderson 1960) comb. nov., Tschudypollis retusus (Anderson 1960) comb. nov., and Tschudypollis thalmannii (Anderson 1960) comb. nov. The palynofloral taxa include 67 angiosperms, eight gymnosperms, 19 pteridophytes, and three bryophytes. Of these, 33 are regarded as characteristically uppermost Cretaceous taxa (K taxa). A few of the K taxa do not range all the way to the K-T boundary. Extinction of the&amp;nbsp;&lt;/span&gt;Hell&lt;span&gt;&amp;nbsp;&lt;/span&gt;Creek&lt;span&gt;&amp;nbsp;palynoflora at the K-T boundary is ∼30%. The&amp;nbsp;&lt;/span&gt;Hell&lt;span&gt;&amp;nbsp;&lt;/span&gt;Creek&lt;span&gt;&amp;nbsp;&lt;/span&gt;Formation&lt;span&gt;&amp;nbsp;is within theWodehouseia spinata Assemblage Zone.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1130/0-8137-2361-2.393</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Geological Society of America</dc:publisher>
  <dc:title>Palynology and palynostratigraphy of the Hell Creek Formation in North Dakota: A microfossil record of plants at the end of Cretaceous time</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>