Please help me with the names of these shellfish fossils

[shaman]

Last weekend I've found a bunch of shellfish fossils close to the seafront rocks in Western Algarve in Portugal. Could you please, help me and identify them? I separate the fossils in 5 different groups regarding their shape from type 1 to type 5.

Country: Portugal
Province: Algarve (West Part)
City: near Alvor 
Location details: Found near beach rocks
Scale used in photos : mm/cm

 Type 1 :

 

 

Type 2:

 

Type 3:

 

Type 4:

 

Type 5:

[westcoast]

These are quite fragmentary and also bioeroded, better preserved specimens would be needed to identify them properly but somebody familiar with the location might be able to say more. Some of the pieces look like bits of cockle shells.