Corals are common in Ordovician, Silurian, and Devonian rocks from Alaska, but few have been described or illustrated. Most of the known occurrences of corals are in carbonate rocks, either in an east-west belt of shelf facies across central Alaska that presisted from pre-Ordovician to Middle Devonian time or in a more southerly volcanic graywacke belt of geosynclinal facies that includes significant limestone units in southeastern Alaska. Corals occur in other areas but are less well known.
Annotated lists of corals summarize most collections made by U.S. Geological Survey geologists in the last 15 years. Many of the corals are illustrated.

1) 66ATr82.3, -.4, -.5 and -.6, include no corals. Tom Dutro indicates that 82.3 and 82.6 are certainly Silurian on the basis of the brachiopods. A report will follow.

2) 66ATr109, 109.3, 109.5, 110.2 and 111, are dominantly corals and are covered in the following report. Most specimens are rather poorly preserved and one collection lacks recognizable megafossils. The other four collections probably fit into the range of time represented by Middle and early Late Devonian although only 109.5 is reasonable definite. The other three collections include Amphipora? and my age statement is based entirely on this form, only questionably identified in each case.

Material on which the age statements are based is being retained for our reference collection. The indeterminate material and cuttings will be discarded unless you indicate that we should return it.