28:
The
Cassinian is named for the Fort Cassin Formation of Vermont. Rocks of Cassinian age are found in the Champlain Valley and among other places in North America in the Great Basin of Western Utah and Nevada, and in the uppermost El Paso Group in southern New Mexico and west Texas.
24:
when thought of temporally and the uppermost stage of the
Canadian Series when thought of stratigraphically. The Canadian, either as a series or as an Epoch is the name that has been given to the Lower, or Early, Ordovician in North America and has been applied worldwide.
47:
which has been sought to replace the
Canadian as the Lower Ordovician in North America. However the Ibexian, named for the Ibex region in western Utah, extends 2.7 .m.y. into the Cambrian taking up more than half of the
43:, both spanning the same 6.8 million years. In the four part Canadian series, the Cassinian is late upper Canadian, preceded by the Jeffersonian, and is equivalent to the upper Blackhillsian stage of the
32:
The
Cassinian has been given a span of only 1.2 million years, with a range from 473 - 471.8 m.y.a. which may be short, looking at the El Paso section and Early Ordovician cephalopod evolution
79:
Flower, R. H. 1964. The
Nautiloid Order Ellesmeroceratida (Cephalooda), Memoir 12, State Bureau of Mines and Mineral Resources, Socorro, New Mexico.
56:
and by the newer ICS Dapingian, given respective durations of 9.8 and 3.7 m.y. and in older chronologies by the 7.8 million year
Llanvirnian.
116:
Teichert et al, 1964. Treatise on
Invertebrate Paleontology Part K Mollusca 3, Teichert and Moore eds.
132:
105:
21:
126:
49:
53:
36:
44:
40:
91:
Moore, Lalicker, and
Fischer 1952. Invertebrate Fossils, McGraw-Hill
52:. The Cassinian is followed in North America by the
35:In worldwide terms the Cassinian is upper, or late
39:which is exactly equivalent to the newly proposed
8:
101:
99:
97:
75:
73:
71:
67:
87:
85:
7:
14:
1:
149:
20:is the latest age of the
140:
117:
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108:
103:
92:
89:
80:
77:
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120:
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111:
104:
95:
90:
83:
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69:
64:
12:
11:
5:
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135:
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109:
93:
81:
66:
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63:
58:
22:Canadian Epoch
13:
10:
9:
6:
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3:
2:
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50:Trempealeauan
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33:
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26:
23:
19:
112:
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54:Whiterockian
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31:
27:
17:
15:
61:References
133:Paleozoic
37:Arenigian
18:Cassinian
127:Category
107:Geowhen
45:Ibexian
41:Floian
16:The
129::
96:^
84:^
70:^
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