I am a descendent of Shadrach Turner of Prince George, MD.My research data differs somewhat. The use of the name John throughout the generations can cause confusion.
Shadrach Turner born 28 Dec 1732/3 died 2 Oct 1799 wed Sarah ? who died on April 12, 1819. Their children were Thomas, Ann, Rebecca, Elizabeth, Samuel, Dorcas and John.
Shadrach was the son of John Turner born 1696/97and died in 1738 in Prince George County MD. John married Elizabeth Brashears on July 1, 1718. Elizabeth was the daughter of Samuel Brashears of Calvert, Md and Ann Jones of Queen Anne, Talbot Md. Elizabeth was born July 27, 1699 in Calvert, MD. Their ten children were Sarah, John, Elizabeth, Ann, Samuel,--rnett, Rachel, Shadrach, Dorcas,& Philip.
The 1696/97 John Turner was the son of John Turner circa 1671 and Sarah Bevens (Bevins). They wed circa 1695 and had 8 children: John, Solomon, Margaret, Elizabeth, Sarah, Anne, Matthew,& Dorcas. John died circa 1723 and Sarah Bevens died 1739.
The 1671 John Turner was the son of John Turner and Margaret Cornwell Turner. John was born in 1653 and died in 1705. Margaret was born in 1649 and died in 1709. Their 4 children were John, Ann, Dorcas, and Mary.
The 1653 John Turner was the son of William Turner of England. He was born in 1627 and died in 1663 in Calvert, MD. His children, William 1655, John 1653, Richard 1661, Edward 1657 and Jane 1659 were born in England. William Turner came to the US before 1653 with his wife and sons and servant Hobart Pitty.
For further info, see the LDS familysearch site, the Prince George, MD index of church records for Queen Anne Parish, and Index to Registry of King George Parish, AKA St. Johns Parish at Borad Creek, pg 348 of Colonial Settlers of Prince George County, MD & The Early Settlers Of Md