Formal metadata: information and software
A practical plan to support finding scientific data from many sources inside USGS.
Since you don't know what's available, and you're willing to learn about what we have, you don't want to have all of the details of the databases or of the records themselves put in front of you just yet-- instead, you want to read a little, then click on the ones that seem relevant to your concerns. You might visit the database home page, but you might first look at a few records from that database to figure out whether it's the sort of data that might help you.
People in USGS who manage web access to a particular scientific database create a search web service that accepts a geographic location and a tolerance, or a bounding box, and returns a list of records in JSON format. In addition to the search service, they will need to make it so each record in their database has a URL and they can provide the complete data for that record in JSON or HTML.
Some people create map interfaces or other geographic search interfaces that compose queries for those scientific databases and get results back from them. They show the results to you in formats that work for you.
To a large extent, this isn't "owned" by any one organizational unit within USGS.
Anybody can create a web interface that does the searches, you just need to know which services are available.
People can encounter this type of search from a map interface, or by clicking a single link labeled something like "Show other scientific data near this location" that could be on a web page describing a point location like a stream gage, mine site, geochemical sample, bird nest, or other location of interest.