I have deleted a couple of thousand pages from a website. They do not appear in my sitemap.xml and no other pages on the web are pointing to these anymore.
Google Webmaster Tools (GWT)'s crawl error pages starts to report them as not found. There is an option to mark them as fixed. Should I mark them as fixed? They are not really fixed and won't ever be fixed.
There is also a remove URLs page, but there is no way I will manually remove those pages one by one (REM: those pages are not in a single directory, they were all over the place, so there is no robots.txt directive I could use).
If Google does not find a page, does it automatically remove it from its index, or if we mark it as fixed, does it try to reach it over and over again?