Complex sentence: Local people also believe that "Hanumagiri" is part of Sanjeevini mountain which was "dropped" by Lord Hanuman while he was bringing it to cure Lord Ram and his brother Lakshman who were injured during Ramayana.
Split into simpler sentences: Local people also believe that "Hanumagiri" is part of Sanjeevini mountain. The hill is believed to have originated after being "dropped" by Lord Hanuman as he was bringing it to cure Lord Ram and his brother, Lakshman, who were injured during Ramayana.