Stories in the elementary class are not limited to the Great Lessons. There are many stories to accompany other lessons and concepts - some are variations of those created by Mario Montessori and the key Montessorians that cultivated Dr Montessori's concept of cosmic education. Some stories are handed down from trainers, some are original creations of individual teachers.
I have read (and heard!) several different versions of stories about the gift of plants, the piece of paper that speaks, the multitude, the black pyramid, the four strange brothers, the first counting, the story of tan, the triangles club, the three kings, and so many more. These stories capture and spark the child interest in concepts that are more abstract than what they have previously experienced.
My favourite resource for cosmic education and story telling is Children of the Universe by Michael and D'Neil Duffy.
I am looking forward to getting my hands on a copy of the newly released The Deep Well of Time (which is proving difficult here in Australia) by master story teller and Montessorian, Michael Dorer. There are already whispers of a follow up book.