SURVEY GEOLOGICAL SITUATION COLLECTION SSS
Period	Epoch	Number of records	Estimated age
			Million Years
Quaternary	Holocene	1191*	0,01
	Pleistocene	2599	1,8
Tertiary	Pliocene	7248	5,3
	Miocene	8515	22,5
	Oligocene	1354	33,9
	Eocene	11582	55,8
	Paleocene	858	65
Cretaceous	Upper Cretaceous	229	99,6
	Lower Cretaceous	47	145,5
Jurassic	Malm	36	161,2
	Dogger	41	175,6
	Lias	34	199,6
Triassic	Upper Triassic	0	228
	Middle Triassic	2	245
	Lower Trisssic	0	251
Permian		0	299
Carboniferous	Upper Carboniferous	9
	Lower Carboniferous	4	359,2
Devonian		127	416
Silurian		8	443,7
Ordovician		11	488,3
Cambrium		1	542
* In 2009 we donated 20.399 records containing 96.290 shells to the University of Amsterdam