A computerized system that implements a type system can process one or more XML documents that comprise unknown schema elements, which may not correlate within one or more types in the type system. In one implementation, for example, a computer system receives one or more XML document feeds and deserializes only those schema elements that correlate with one or more system types. The computer system further passes the unknown schema elements to a buffer. An application program, such as an XML reader, can extract the unknown schema elements from the buffer as appropriate. In one implementation, for example, the application program maintains its own types separately from the system types. The application program can then correlate its application-specific types with the buffered schema elements to deserialize and process the buffered schema elements.