Reference Detail of

Letter from W.B.N. Berry to William P. Brosge
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Stratigraphic range: Ordovician
Kinds of fossils: Graptolites
Quadrangle or area: Demarcation Point
Shipment No.: No Data
Referred by: Brosge, William P.
Report prepared by: Berry, William B. N.
Date: 09/15/1971


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Brief statement of problem and remarks (from collector):
This single specimen is from black phyllite that is associated with (and apparently above) volcanic rocks. Upper Cambrian trilobites occur at the base of similar volcanic rocks about 20 miles to the south. Claire Carter and Charles Merriam agree that the creature is a graptolite, and therefore post-Cambrian. Is it preserved well enough to say whether it is Ordovician or Silurian? (from transmittal sheet of W.P. Brosge)

User Note module to be added
71ABe430D , Demarcation Point , Demarcation Pt. Quad; 69 deg. 26.5' N., 141 deg. 00' W. Collectors: W. P. Brosge, R. L. Detterman. Isoclinal syncline? of black slate-phyllite with very thin beds of limonitic fine-grained sandstone. Abundant worm trails at one or two horizons. 71ABe430D and 71ABe431E. One specimen of biserial graptolite 71ABe430D submitted on a separate request. 500+ ft. Road River Formation (in Neruokpuk terrain).
a robust diplograptid type belonging to either the genus Orthograptus ....
.... or the genus Diplograptus.