The word Graowacke is misspelled against Grauwacke, a noun meaning "Graywacke."
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Word contains consecutive vowels 'AU' in between alphabets gr & wacke is misspelled as 'AO'
Wrong Spelling:  gr-ao-wacke 
Correct Spelling:  gr-au-wacke 
Find more incorrect spellings of Grauwacke to spell right way.