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Reference
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| Title: |
Report on Referred Fossils
,
1956
(05/23)
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This report covers six collections of predominantly graptolitic material from the Thorne Bay vicinity, Prince of Wales Island, southeastern Alaska. Five of the collections made up the original shipment and one collection (55AHd330) was sent to me at a later date. Two of the collections contain genera that pinpoint the age of the enclosing rocks. 55AHd330 is probably of Middle Ordovician age and 55ASn125 is probably of Lower Silurian age. Sainsbury has indicated that he believes all these collections, except perhaps 55AHd330, come from the same rock unit. He points out that 55ASn216 and 55ASn240 are probably from the same bed and that 55ASn125 is considerably higher in the section than 216 and 240. On the basis of my rather meager knowledge of graptolite faunas, it is possible that all the material, except collection 55AHd330, is of Lower Silurian age. The generic composition of these collections is similar. On the other hand, certain elements of 55ASn184 lead me to suspect that it may be slightly older. If so, it is likely that 55ASn216 and 240 are the same age. One possibility is that Sainsbury's map unit embraces beds of Ordovician and Lower Silurian age. A simpler solution, until more faunal detail is secured, is that the unit be called Lower Silurian, supplemented by a discussion of the possibility that older beds are included. |
| Report by: |
J. Thomas Dutro
, Jr.
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| Referred by: |
C. L. Sainsbury
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| | Age: | Middle Ordovician |
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| Comment: | The age is Middle Ordovician. |
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