collections in scala

Traversable is the base trait with abstract method foreach and many other concrete classes to manipulate collections.
foreach is implemented in sub trait Iterable.
Iterable have abstract method iterator.
Iterable have three sub trait Seq,Set and Map.
All concrete classes  under Seq,Set and Map either mutable or immutable.
scala.collection is the base package.
It has sub packages scala.collection.immutable and scala.collection.mutable.