decoding federal city college logo

I love this Federal City College logo! It is reminiscent of a microscopic view, a petri dish, a 'you are here' way finder at a mall and a pin-back button.  

I'm in the process of creating a logo and will definitely be using this logo for inspiration.

Before the current UDC location in Van Ness, FCC used several locations including 425 2nd Street NW.  I believe the arrow is pointing to that address.

Here's what I'm not sure about.  What is the 'obelisk' jutting out from the upper right of the circle and what do the '2' and the 'D' signify?

Did you create this logo? Were you a student, administrator of faculty member @FCC in 1968?  Or are you a great logo decoder?  Do share.

Source:  I thank Faith A. Rusk, Information Literacy Instruction Librarian @UDC, and Christopher Anglim, Archivist @UDC, for these images.