how datatpes are mapped in xml schema syntax

[Vinay Punnoose]

Hi, 
Somewhere I read that for maximum platform neutrality, WSDL uses XML
Schema syntax to define data types. But I couldn't map any of the
datatypes to the XMLSchema syntax.
Like I couldn't find a mention of 
"xsd:string" or "xsd:float" on
http://www.w3.org/1999/XMLSchema.xsd
I don't know how to read xsd though, but i think atleast the string,
float or such things should be there.