My sitemap looks like this:

−
<sitemapindex xsi:schemaLocation=" Index of /schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/09/siteindex.xsd">
−
<sitemap>
<loc>http://www.mydomain.com/sitemap_1.xml.gz</loc>
<lastmod>2008-08-09T18:57:58+00:00</lastmod>
</sitemap>
</sitemapindex>


This is the only code I can see in my generated sitemap. I run a forum with 3500 threads. Can someone confirm that my sitemap looks okay?

The reason I ask this is the fact that on other sites my automatically generated sitemaps include a large list of urls... and this looks very empty to me..

I think I found it... It points to another sitemap with all the urls...

That is correct. This is the index sitemap. Which will show the multiple seperate sitemaps. (Example sitemap_1, sitemap_2 and so on).