# Deep Sea project (4):  132 active drill-site columns
  Cambrian	0	0.0%
  Ordovician	0	0.0%
  Silurian	0	0.0%
  Devonian	1	0.8%
  Carboniferous	0	0.0%
  Permian	0	0.0%
  Triassic	0	0.0%
  Jurassic	2	1.5%
  Cretaceous	46	34.8%
  Paleogene	84	63.6%
  Neogene	105	79.5%
  Quaternary	123	93.2%
sites holding Jurassic through Quaternary:  2;  Cretaceous through Quaternary:  29
oldest system held:  Cretaceous 43, Paleogene 42, Jurassic 2, Neogene 28, Quaternary 16, Devonian 1

## Land columns, layered units:  1361 columns with Phanerozoic units
share of each column's own span (oldest base to youngest top) covered by units:  quartiles 30.6%, 56.9%, 82.7%
share of the whole Phanerozoic (538.8 Myr) covered:  quartiles 7.4%, 15.2%, 29.4%;  max 92.3%
resolved gaps per column:  median 3, upper quartile 6, max 19

## Deep Sea drill sites, sedimentary units:  132 columns with Phanerozoic units
share of each column's own span (oldest base to youngest top) covered by units:  quartiles 55.0%, 79.0%, 100.0%
share of the whole Phanerozoic (538.8 Myr) covered:  quartiles 1.8%, 4.3%, 9.7%;  max 24.8%
resolved gaps per column:  median 2, upper quartile 5, max 26

Limits:  unit ages are the compilers' correlation ages on the mainstream timescale;  a gap shorter than a compiled unit is invisible, so these coverages are upper bounds at Macrostrat's resolution (the Sadler effect).