How to write a bibliographic cite for multiple USGS topo maps

Factual Questions
1

I’m finishing up writing a book and I’m doing my bibliography. I’ve come across something that I can not seem to find a way to write the source for. I am dealing with small cemeteries and sometimes they come up on the USGS topographical maps. Normally the 1:24,000 scale. I looked over 10-12 from the 1940s-present.

I have seen examples for one topo map, but not for multiple at a time. I’ve got a copy of Elisabeth Mills’ Evidence Explained, while it has how to do it for the single map, it doesn’t say how to do it for many of them. Since I probably looked at 30+ maps, I don’t want to do something for each one as many of them didn’t have anything useful.

I didn’t actually use any as cites, but I do want to say that they were looked at. Is there a good way to do this?

2

Without consulting any bibliographic style guide, I’d probably do something like:

United States Geological Survey. Topographic maps: various quadrangles, scales, years.

If they were all the most modern 1:24,000 scale, you can put that or “7.5-minute series” in as the scale. But a few modern maps were 1:25,000, and the older ones were 1:62,500. If you want to be encouraging to modern readers, you could add “Available online at topoView | USGS”

3

The Bedford Handbook gives an example of a map cite:

Fred Zwicky; NIAMS; Arizona Board of Regents; Lynn Hunt et al.

Hope this is of use.

4

I ended up going with Mr_Downtown’s suggestion. There was an entry for multiple dates of newspapers that was similar.