Sample Detail of
Sample: Sample No. 55ASn125
Locality: Field No. 55ASn125
Description: None given in E&R form, however transmittal sheet of Sainsbury states: "Graptolites from west side Thorne Bay, coordinates 6.2, 11.5, Craig C-2 quad. Probable age from Buddington's map (Bull. 800) is Devonian. [Note by R.B. Blodgett: Sainsbury (1961, USGS Bull. 1058-H, p. 321 gives further information: "Lat. 53o 39'56" N., long. 132o 30'40" W., west shore of Thorne Bay, opposite entrance."][Additional note by R.B. Blodgett; obviously the lat. of 53o given above should be 55o]
Location: Alaska Quadrangle: Craig C-2
Lat.: 55o39'56 " Long.: 132o30'40 "
Reference
Title: Report on Referred Fossils ,  1956 (05/23)
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.
Referred by: C. L. Sainsbury
Age: Early Silurian
Comment:Contains Rastrites, Climacograptus?, Monograptus, Lingula, Orbiculoidea? and indeterminate pelecypod fragments. The age is Lower Silurian, based on the occurrence of Rastrites and several monograptid types.
Occurrence(s)
No. Group Name Qty Notes
1 Graptolites Rastrites
2 Graptolites Climacograptus?
3 Graptolites Monograptus?
4 Brachiopods Lingula?
5 Brachiopods Orbiculoidea?
6 Bivalves indeterminate pelecypod fragments