Postcard of former school house in Avis, Pennsylvania

What a building! Every time I see a postcard or photo of an old school of this type, I think of the building that's described so perfectly (and forbodingly) in Dan Simmons' 1991 horror novel Summer of Night. 

The front of the postcard indicates that this is the School House in Avis, Pa. If you look closely, two numbers have been written on the building. Under the photograph, the handwriting states: "(1. my room before noon) (2. my room afternoon) L.B.B."

Avis is a tiny borough in northcentral Pennsylvania, about 18 miles west of Williamsport. Its population took a big jump in the 1960s and has been steadily around 1,500 for the past three decades. 

This postcard was mailed from Avis to Mrs. L.E. Campbell in the logging town of Cross Fork sometime in the 1910s.

The cursive message states:

Dear Mrs. C. — Suppose you will be surprised to hear I have another position as Grammar Grade Teacher here. Like it first class, yet the offer was a surprise have 40 pupils of my own and in afternoon have part of the High School students in my care. Don't know how long I'll have to stay the regular teacher has a broken arm, may be here 3 wks, maybe 3 mo, Write me a long letter soon, Love to all.

Your friend

Leah, Avis, Pa.

So, Leah is L.B.B., but that's the extent of what we know of her name. Surely that won't be enough to indentify this substitute teacher of a century ago. Too bad.