These photos were taken on Tuesday March 8, 2016. They have just chewed off the NE corner of the school, roughly to the doorway separating the cafeteria from the kitchen.
As shown in this 1920's postcard they are at exactly the point where the original structure ended along 4th Street. On the basement level that was where the underpass to the courtyard was located. It was installed when the wings were extended toward Church Street to provide access to the service doors in the courtyard, the most important of which was the hatch to the coal bunker.
Note the stone wall in the foreground of the these photos. It was the north side of the 1870's high school.
One of the old heat exchangers has become visible at the bottom corner of the above photo, also note the brick air shaft whose edge has been padded with the orange mat. These were constructed between the two buildings when the 1870's high school was still standing.
These are the most interesting shots that I have taken as they reveal the stone foundation walls of the 1870's high school. The 1870's school remained standing and in operation as a Junior High School for several years after the "L" shaped Cottage Street portion of the new school was built. They shared a forced air heating system which is why there are smoke stacks directly above this point. The gym was then built over the 1870's stone foundation. I believe that the indented section containing the orange mats was the front door of the 1870's high school or at least where it was located.
The above photo nicely illustrates that it really was quite a pile a bricks. The steel door to the right provided access to the south air shaft and the doorway below it was at the west end of the basement hallway leading to shop area, just inside this door is the stairway from the basement to the first floor.