Markings on the Curbs

OK, I realize this is pretty trivial, but I have noticed these markings on a lot of the old granite curbs. Sometimes there are channels cut out for downspout drains, and sometimes there are even iron eye-hooks set in the stone. Here are a few photos snapped while walking around the past few months:


An arrow:

Arrow:

A "T":

An "F":

A "GF"?:

Another T:

An "E":

A triangle, this one in concrete:

An "A":

Blobs or squares:

A 'D"?:

An E:

box with lines down:

Box with a dash:

Dash in a box:

A summary of the above shapes:


I think the left half are all water valve symbols. I would guess the E is electric and T for telephone?