The Vital Records for Nantucket (1850) show Charles E Pinkham, b. 21 Jan 1841. His wife is not given since the marriage would be after 1850. However, he had a sister, Helen E. Pinkham, who married Charles O. Burton “of California”. Helen E. was born 11 Dec 1836, and so was about 4 years older than Charles E. She might well have been the catalyst for him moving to California (and why he named one of his daughters Helen). Here is the male line:
Charles E. Charles F. m. Susan W. Miller Reuben G. m. Mary Sanford Uriah m. Saloma Gardner Peleg m. Jemima Swain Peleg m. Elizabeth Swain Richard (first in Nantucket) m. Mary Coffin Richard of Dover m. Gylian
As you can see, this line ties into some of the main Nantucket families: Gardner, Swain, and Coffin, and looking further back, Starbuck, Folger and Barnard. I have more info on this pedigree if you need it.