Sentence:  The "simple" metaphor, such as the instance given, becomes the "continued" metaphor when the analogy or similitude is worked out in a series of phrases and expressions based on the primary metaphor; it is in such "continued metaphors" that the <WSD>solecism</WSD> of "mixed" metaphors is likely to occur. 
Meaning of the word marked with <WSD> tags:  Error in the use of language.