Martin (1992: 521):
Field-structured texts constituting a social process are sensitive to the length of time-line in focus. The longer the time-line, the more selective the coverage. These texts can therefore be crossclassified [sic] as episodic (e.g. biography) and primarily organised through setting in time (typically theme marked circumstantial adjuncts) or sequential (e.g. narratives) and primarily organised through sequence in time (typically by temporal conjunctions).
 The use of the word 'texts' here betrays the ongoing confusion between text types (registers) and context (mode). The confusion is thus along two theoretical dimensions simultaneously: stratification (context vs language) and instantiation (system vs instance type).
 This confuses mode potential with the ideational meaning of text types. The confusion is thus along three theoretical dimensions simultaneously: stratification (context vs semantics), metafunction (textual vs ideational) and instantiation (potential vs instance type).