BELEMNITES OF ALASKA—RENEWED STUDY WITH A FOCUS ON LAKE CLARK NATIONAL PARK

Publications on belemnites (Mollusca, Cephalopoda) of Alaska are few and most were written over half a century ago. Various sources document belemnites from Arctic, southwest, south central and southeast Alaska. However, in many cases details are lacking, specimens are not identified, and revisions in systematics and dating have occurred. We are engaged in a project to identify all published references to Alaska belemnites; to locate and identify Alaskan specimens in museum collections; compile data from USGS evaluations and reports; and identify recently collected specimens. The focus of this report is the belemnite fauna of the Tuxedni Group (Middle Jurassic, Bajocian) exposed near Fossil Point, Tuxedni Bay, Alaska Peninsula, in Lake Clark National Park.

Specimens of invertebrate macrofossils were collected in August 2014 as part of a Park Service fossil inventory of Fossil Point. The fossil assemblage consists of bivalves, ammonites, and belemnites. Five belemnite specimens were collected from float of the upper 25 meters of the Red Glacier Formation and brought to Anchorage for photography and preparation. Four were photographed in situ in the Red Glacier Formation and Fitz Creek Siltstone but not collected. Those collected included a phragmocone with an oval cross section. The size and shape were suggestive of Megateuthis, but without a rostrum this cannot be confirmed. Another specimen consisting of two partial rostra in matrix showed features suggestive of Cylindroteuthis, but since the apices were missing, this also is only a tentative diagnosis. The most complete rostrum collected has been identified as Pachyteuthis, possibly of a species not previously documented. Evaluation of this specimen is still in progress.

Megateuthis, Gastrobelus, Cylindroteuthis and Pachyteuthis have been documented in museum collections from Jurassic formations of the Alaska Peninsula but no details on localities are stated and the specimens are not figured (Stevens, G. R. 1965). The paleogeography of belemnites reflects their migration patterns and locations of terranes in the Jurassic. Therefore, further characterization of this group in Lake Clark National Park may contribute to our understanding of the history of the Peninsular terrane in the early Middle Jurassic.