Solecism

[…]to suppose that the general concern of this Country can be directed by thirteen heads, or one head without competent powers, is a solecism, the bad effects of which every Man who has had the practical knowledge to judge from, that I have, is fully convinced of; tho' none perhaps has felt them in so forcible, and distressing a degree.

Source: wiktionary

Why leave the non-enumerated articles, covered by the act of 1864, subject only to this lower rate of duty? Why this distinction? Such a result would, we think, be a solecism, and contrary to the spirit and purpose of the act. It cannot reasonably be supposed that such was the intent of the clause in question.

Source: wiktionary

For this reason she was fond of seeing great crowds and large stretches of country, of reading about revolutions and wars, of looking at historical pictures—a class of efforts as to which she had often committed the conscious solecism of forgiving them much bad painting for the sake of the subject.

Source: wiktionary

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 solecism of "mixed" metaphors is likely to occur.

Source: wiktionary