I am related to Lavinia Pelham through her daughter, Sarah Mabee. She is my 4th great grandmother and was married to Silas Montross. I can give you an up-to-date direct descendent lineage through their son Wilson, if you would like.
The Montrose name ended with my grandfather, Rodney Hill Montrose. He only had two girls. Both my brother (who has two girls also) and my son have Montrose as their middle name. That is the only way it can be carried down on my side of family.