Sarcasm production and comprehension have been traditionally described in terms of pragmatic factors. Lexical cues have received less attention, but they may be important potential indicators. A major obstacle to examining such features is determining sarcastic intent. One solution is to analyze statements explicitly marked as being sarcastic. This study examined Twitter postings marked with #sarcasm as well as dialog from Google Books containing the phrase "said sarcastically." We used word counting and part-of-speech tagging to compare specific lexical features of the explicitly-marked sarcastic statements to statements by the same author not marked as sarcastic. Our results broadly support the Lexical Cues Hypothesis--certain word-level cues, such as interjections and positive affect terms, are stereotypic of sarcasm. A model incorporating these features performed comparably to human raters in making sarcastic versus nonsarcastic judgments. This finding shows promise for future work toward automatically identifying sarcasm in text.