WW2 Invasion of Poland Germans Digging Trenches for the Battle of Lwów (Lviv)

Description

Given the other photographs in this set, and the numbering used, this is likely somewhere near
Janow, Poland or outside of Lwow preparing for the siege of the city on or around the 19th of
September.
In German:
Stellungsbau in der Slowakei
Building fortifications in Slovakia
I am assuming that using Slovakia is using it as a general term for the area.
The battle of Lwow took place from 12 - 22nd of September and marked the entrance
of Russia in to the war.  The German soldiers possibly are in Janow, defending against
reinforcements from central Poland reaching Lwow, which is now modern day Lviv, Ukraine.
An extremely rare photograph from the very first days of the war.
Measures approximately 4 by 2 3/4
Box J 09292021
Weight 0 ounces