Complex sentence: To show that he had not used such tricks, McCay chose a creature for his next film that could not have been photographed: a "Brontosaurus" in "Gertie the Dinosaur", which debuted as part of his vaudeville act in 1914.
Split into simpler sentences: To show that he had not used such tricks, McCay chose a creature for his next film that could not have been photographed: a "Brontosaurus". The film, "Gertie the Dinosaur", debuted as part of his vaudeville act in 1914.