[Leaning Right]

Orthodox Jewish women cover their hair with either a kerchief or a wig, and dress modestly.

And they always wear dresses, always. Never jeans or pants of any type. The dresses are rather plain and long, going down almost to the ankles.

And high socks are always worn. It is considered immodest for a woman to expose any part of the leg, or arm for that matter.

[EinNYC]

The dresses are rather plain and long...

Are you describing members of Warren Jeff's cult or Orthodox women? From your description, I'd say the former. Orthodox women may dress modestly, but they dress fashionably. They generally wear nylon stockings, not high socks. They are allowed to show their legs below the knee, and most groups of Orthodox allow showing the arm up to the elbow. Only some Chassidic groups insist on sleeves to the wrist.

Warren Jeff's women:

Regular Orthodox women in Brooklyn: