A further problem is that in the southeastern US, in the latest of those megasequences, there are about 20 shorter term (500,000-10,000,000 year) pulse, and about 200 Milankovitch cycle-based ones within those. Each one of the 20 pulses has noticeably different organisms, including many found in no other layers.
A generalized sequence:
Wando Formation and equivalents (Milankovitch highs in last ~200 kya) Shelly sand
Canepatch Fm. and equivalents (~300 kya-500 kya) Shelly sand
James City Fm., Ft. Thompson Fm., and equivalents (~700 kya-1.2 Mya) Shelly sand
Bermont Fm. and equivalents (~1.4-1.6 MYA) Shell hash with sand
Faunal Turnover (<10% extinct species above, >40% below) Carolinapecten extinct and Pterorytis exterpated
Waccamaw Fm., Caloosahatchee Fm., and equivalents (~2.4-1.8 MYA) Shell hash with sand
Chowan River Fm. and equivalents (~2.8-2.6 MYA) Shell hash with sand
Faunal Turnover (50-70% extinct above, 80-90% below)–Chesapecten and Ecphora extinct
Yorktown Fm., Goose Creek Limestone Jackson Bluff Fm., Tamiami Fm., and equivalents (~3.2-4.4 MYA) Shelly Mud, Shelly Sand, Limestone.
Eastover Fm. and equivalents (~6-8 MYA) Limestone
St. Marys Fm. and equivalents (~11.7-12.5 MYA) Limestone
Pungo River Fm., Calvert Fm. & Choptank Fm., and equivalents (~13-19 MYA) Phosphatic shell hash, Limestone
Chipola Fm. and equivalents (~20-23 MYA) Chesapecten and Ecphora appear sandy shell hash or limestone
Belgrade Fm. and equivalents (~23-25 MYA) Limestone
River Bend Fm. and equivalents (~25-30 MYA) Limestone
Castle Hayne Fm. and equivalents (~34-44 MYA) Limestone
Congaree Fm., Nanjomoy Fm., OIdsmar Limestone, and equivalents (~43-55 MYA) Limestone
Beaufort Group, Black Mingo Group, and equivalents (~56-65 MYA) Limestone
K-T Boundary Exogyra, ammonites, and mosasaurs extinct
Peedee Fm. and equivalents (~65-71 MYA) Clayy Mud, some mudstone