となる with a sense of composition


There are already posted
[questions](https://japanese.stackexchange.com/questions/47659/meaning-of-
verb%E3%81%A8%E3%81%AA%E3%82%8B) (and answers) for the meaning of となる as a
similar pattern to になる, but with a sense of finality.

However, I've come across the following sentence

> A棟{とう}は、１階が寮長{りょうちょう}の部屋と食堂{しょくどう}、２階が男子で、３階が女子のフロアー **となっていて**
> 、B棟{とう}は男子学生のみだった。

where なる as a meaning of "consist" or "be composed of".

My question is, how is the となる construction affected if なる does not have the
usual meaning of "becoming", but one of "consisting"? Specifically, what is
the meaning of the bold part?

Edit:

For clarity, I already know that なる can mean "to be composed of". What I'm
looking for is the nuance of に vs と when なる is used with this sense.

With the "become" meaning, と adds a sense of finality, like "has finally
become". What is the corresponding nuance in with "composed of"? "Has finally
become composed of" does not make sense in the example sentence...




The verb is in the formとなっている which you could construe in this context as “has
become”. But that would result in an awkward translation in English. So,
“consists of” seems like a reasonable translation.

But what seems reasonable to me aside, check out Kenkyusha’s New Japanese
English Dictionary. This dictionary (at least my print addition which is over
20 years old at this point) lists 14 subheadings under なる. Subheading 4 lists
the following renderings for the verb: consist of, be composed of, be made up
of, be formed of.

Keep in mind that very simple verbs like なる can have very broad and subtly
nuanced meanings/uses. It’s best not to try to force one English translation,
_become_ , into another, _to consist of_. It’s better to read (or listen) to a
wide range of genres to begin to get a sense of the subtle nuances of these
words.

