maa yamuna is worshipped in yamunotri in form of divya shila.in the same way as lord shiva is worshipped in form of shivlinga.it is her another presence here in different form or incarnation, alongside her nationwide presence as river yamuna. yamunotri is the only known source of river yamuna that is visible to human eyes in kaliyuga. as told in mahabharata , river yamuna originates from the foot of jamuna tree which is invisible to any being born in kaliyuga .only beings born before kalyuga can see that jamuna tree. maa yamuna is lord surya's daughter , lord krishna's wife & lord yamaraja's sister