Of these collections, AC 3, AC 13, AC 20, AC 34, AC 37, AC 1082, AC 2112, AC 6002, and probably AC 54 and AC 6001 can be dated as late Karnian or early Norian (medial Late Triassic). Collections AC 1131, AC 1163, AC 2113, and probably AC 33, AC 35, AC 51, AC 1165, AC 3007, and AC 5004 are of middle or late Norian (late Late Triassic) age. Collections AC 29, AC 36, AC 50, AC 1079, AC 1081, AC 1117, AC 1130, AC 2010, and AC 3006 can be dated only as Late Triassic.

Collection AC 39 deserves special mention because the pelecypods present are best assigned to the genus Daonella which is largely confined to the Middle Triassic.

Five upper Paleozoic collections, AC 1057, AC 2093, AC 2120, AC 2129, and AC 6000, were included in this shipment and are being forwarded to J.T. Dutro, Jr. for study.

The collections whose locality numbers are underlined in the following tabulation will be added to the USGS reference collections. Locality data for the collections so marked will be appreciated at your earliest convenience.