ID request Kythera island

[Dimitris]

Hello everyone. 

I was collecting in an abandoned sand quarry in the Greek island of Kythera. 

The formation is Tortonian - Zanglean made of various hardness/density sandstone. The upper layer looks like river deposits as it has more round pebbles and its thickness is less than a metre. The main formation exceeds 8m. 

 

North of this place (800m) and south of it (1000-1200m) there are confirmed Miocene deposits, terrestrial and river origin. 

 

I am clueless with this. 2€ coin = 1inch

I thought of mammal tooth but I have no idea of such things. 

My other thought, it is just a rock..