Entries for these categories are in the database, but are not available at the public Web site.
All coordinates in the database are in NAD 83. They were converted from NAD 27 in September 2005. 
The field entitled "Topo Map Name"; indicates the name of a USGS standard topographic map.
There are no official definitions for generic terms as applied to geographic features. Such definitions as exist derive from the particular needs and applications of organizations using them.
Often, users of the data can misinterpret the content of certain fields. The field entitled "USGS 7.5' map" may be one of these fields.