The obituary of Julia Ellen confirms that George Whitehead came to America before his wife and children, but we have not been able to determine the year he sailed to America or the name of the ship. His wife, Julia and her children Julia Elizabeth, George Morris and Charles John sailed to America in 1868 on the ship Colorado.
Note that the obituary of Julia Ellen states that the family came to Utah with the Homer Duncan company, but this is incorrect, as there was no Homer Duncan company in 1868, nor did Homer make a trip back to Utah in 1868. Further research is needed to determine the name of the company with which the family traveled to Utah.
FamilySearch gives her death date as 27 December 1901, but the inscription on her gravestone shows the date as 26 December 1901.