A shell of some sort

[niclasf]

Hi, very new here but hoping to learn. So if anyone how tips on resources to help me identify spices and get a grasp on the timescale, reading geological maps I'd be thankful.

 

Found this at Varmlandsryggen (Karlstadtoppen), West Spitsbergen. Its from my understanding a fold-thrust belt. From paleozoic-mesozoic era (I know big chunk of time, but still figuring out the timescale and maps)

In the area are also lots of corals. Living in Svalbard, so hoping to learn here and also share a growing gallery of fossils from here.

Size is about 4 cm