Choosing broad temporal categories, such as "ARIK Arikareean (30-18.8 Ma)" will yield only sites that cannot be dated more precisely. To find all sites in a larger interval, you must search each of the shorter intervals within it.

Intervals correlate with the radiometric scale as follows:

HOLO LHOL MHOL EHOL WIHO WISC LWSC MWSC EWSC SANG ILLI PRIL EHLG LMHO EMHO FULL GLAC LATE MPLE PLEI RANC IRVI BLAN LLHP ELHP LEHP EEHP LCLA MCLA ECLA LBAR EBAR LHMF EHMF LLAK ELAK LEAK EEAK HEMP CLAR BARS HEMI ARIK EHMP LHMP LARK EARK HPBL CLHP BACL HEBA ARHE WHAR WHIT BLAN

Holocene (10-0 Ka) Late Holocene (4-0 Ka) Middle Holocene (8-4 Ka) Early Holocene (10-8 Ka) Wisconsin/Holocene (120-0 Ka) Wisconsin (120-10 Ka) Late Wisconsin (35-10 Ka) Middle Wisconsin (65-35 Ka) Early Wisconsin (120-65 Ka) Sangamon (132-120 Ka) Illinoian (302-132 Ka) Pre-Illinoian (›302 Ka) Early Holocene/Late Glacial (15.5-7.5 Ka) Late Middle Holocene (6-4 Ka) Early Middle Holocene (8-6 Ka) Full Glacial (20-15 Ka) Glacial (125-10 Ka) Late Glacial (14-10 Ka) Middle Pleistocene (800-400 Ka) Pleistocene (1.8 Ma-10 Ka) Rancholabrean (450-10 Ka) Irvingtonian (1.6 Ma-400 Ka) Blancan (4.7-1.8 Ma) Late Late Hemphillian (5.9-4.7 Ma) Early Late Hemphillian (6.7-5.9 Ma) Late Early Hemphillian (7.5-6.7 Ma) Early Early Hemphillian (9-7.5 Ma) Late Clarendonian (10-9 Ma) Middle Clarendonian (12-10 Ma) Early Clarendonian (12.5-12 Ma) Late Barstovian (14.8-12.5 Ma) Early Barstovian (15.9-14.8 Ma) Late Hemingfordian (17.5-15.9 Ma) Early Hemingfordian (18.8-17.5 Ma) Late Late Arikareean (19.5-18.8 Ma) Early Late Arikareean (23.8-19.5 Ma) Late Early Arikareean (27.9-23.8 Ma) Early Early Arikareean (30-27.9 Ma) Hemphillian (9-4.7 Ma) Clarendonian (12.5-9 Ma) Barstovian (15.9-12.5 Ma) Hemingfordian (18.8-15.9 Ma) Arikareean (30-18.8 Ma) Early Hemphillian (9-6.7 Ma) Late Hemphillian (6.7-4.7 Ma) Late Arikareean (23.8-18.8 Ma) Early Arikareean (30-23.8 Ma) Hemphillian/Blancan (9-1.7 Ma) Clarendonian/Hemphillian (12.5-4.7 Ma) Barstovian/Clarendonian (15.9-9 Ma) Hemingfordian/Barstovian (18.8-12.5 Ma) Arikareean/Hemingfordian (30-15.9 Ma) Whitneyan/Arikareean (32.2-18.8 Ma) Whitneyan (32.2-30 Ma) Blancan (4.7-1.7 Ma)