. Relics of primeval life, beginning of life in the dawn of geological time. Fig. 13.—Arenicolites {Spiroscolex) spirales (Billings) and Aspidella tenanovica (Billings), Signal Hill Series, l^eivfoundland. 54. Fig. 14.—Fragment of Cryptozoon, Grand Cafion, Arizona. Photograph from a specimen presented by Dr Walcott to thePeter Redpath Museum. 56 PRE-CAMBRIAN LIFE $7 Colorado Canon in the Western United States,Walcott has found a small roundish shell of uncer-tain affinities/ a species of Hyolithes, probably aswimming sea-snail or Pteropod, a small fragmentwhich may possibly have belonged to a
. Relics of primeval life, beginning of life in the dawn of geological time. Fig. 13.—Arenicolites {Spiroscolex) spirales (Billings) and Aspidella tenanovica (Billings), Signal Hill Series, l^eivfoundland. 54. Fig. 14.—Fragment of Cryptozoon, Grand Cafion, Arizona. Photograph from a specimen presented by Dr Walcott to thePeter Redpath Museum. 56 PRE-CAMBRIAN LIFE $7 Colorado Canon in the Western United States,Walcott has found a small roundish shell of uncer-tain affinities/ a species of Hyolithes, probably aswimming sea-snail or Pteropod, a small fragmentwhich may possibly have belonged to a Trilobite,and some laminated forms which, if organic, arerelated to the Cryptozoon already mentioned (Fig. 14). The Kewenian series of Lake Superior hasyielded no fossils, but the pipestone beds of Minne-sota, supposed to be about the same age, haveafforded a small bivalve shell allied to Lingula ;^and the black shales of the head of Lake Superiorcontain some impressions supposed to be trails ofanimals.^ It has been a question whether the beds abovereferred to should be regarded as a downward con-tinuation of the Cambrian, or as the upper partof an older system. Matthew, whose opinion onsuch a subjec
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