The POD here is that both sons of George Wittell, Sr., Alex and Junior, survive, rather than Alex dying. In OTL Alex died. When George Jr. runs off with the circus in OTL and the ATL, Senior is more willing to disinherit him because he is not an only child. In OTL he didn't disinherit his only son. Therefore, George Wittell, Jr. remains with the circus and does not return home to San Francisco in 1906.
1828: Hugh Whittell emigrates to the United States from Ireland.
1849: Hugh Whittell heads west to California. Nicholas Luning also arrives in San Francisco. Whittell "grubstakes" the miners, while Luning opens a bank specializing in loans for financially desperate merchants. Both invest heavily in real estate. Luning later becomes one of the founders of San Francisco Water Company (business ancestor of PG&E).
1879: George Whittell, son of Hugh Whittell marries Anna Luning, daughter of Nicholas Luning.
1881 (Sept 20): George Whittell, Jr. and Nicholas Whittell are born to George Whittell, Sr. and Anna Luning Whittell. Soon after, the family moves to their new mansion on Nob Hill.
1884: Nicholas Whittell dies of diphtheria.
1884: Frank Buck is born.
1890: Nicholas Luning dies. Anna Luning Whittell inherits nine million dollars. George Whittell, Sr. uses this fortune to start his own financial empire.
1890's: George Whittell, Jr. graduates from high school and immediately joins the circus. His parents consider disinheriting him in favor of Nicholas Whitell, but refrain from action. Meanwhile, George Whittell, Jr. trains as a lion-tamer. George Whittell Jr. and Frank Buck start a safari business. Anna Luning Whittell convinces George Whittell Jr. to return to San Francisco.
1901: Frank Buck, 17, marries Amy Leslie, a 46-year-old drama critic, in Chicago.
1903: George Whittell Jr. jilts the high society match his parents have chosen for him and elopes with Florence Boyere, a chorus girl. George Whittell Sr. attempts to pay off the bride and county officials to annul the marriage and cover up the scandal. This fails spectacularly.
1903: George Whittell Jr. falls in love with Josie Cunningham, another theater strumpet. George Whittell Jr. marries Josie. George Whittell Sr. finally disinherits George Whittell Jr. in favor of Nicholas Whittell. Junior's fate is now tied to Frank Buck and the circus.
1905: Josie Cunningham divorces George Whittell Jr. and leaves to become an early Hollywood character actress.
1906: Charles Howard, the future owner of Seabiscuit in OTL, tries to rescue family, friends and possessions during the earthquake. Without his friend George Whittell Jr's help, he is lost amid the chaos. Without reconciliation, George never meets his third wife in OTL, Elia Pascal.
1906: The Whittell family (sans Junior) family relocates to Woodside, down the San Francisco Peninsula.
1911: Frank Buck wins $3,500 in a card game and travels overseas for the first time. George Whittell Jr. goes with him.
1911-1929: Frank Buck and George Whittell Jr. travel the world.
1913: Frank Buck and Amy Leslie divorce.
1914: Frank Buck marries Nina Boardman, a Chicago stenographer.
1918: George Whittell Jr and Elia Pascal never meet.
1922: George Whittell Sr. dies. Nicholas Whittell inherits thirty million dollars and invests wisely.
1927: Frank Buck and Nina Boardman divorce. Boardman has developed a loathing of wildlife.
1929: Nicholas Whittell liquidates fifty million dollars in stock holding and transfers it to Nevada, thereby avoiding the 1929 stock market crash and (perhaps) helping to cause it.
1929 (Oct): The stock market collapses. Nicholas Whitell becomes one of the wealthiest men in California. Frank Buck loses everything.
In OTL two back-East financiers wanted to buy the east slope of Lake Tahoe. They recruited Junior for his cash. They couldn't fulfill their part of the deal, and he received sole proprietorship. For decades, as other areas around Lake Tahoe were being developed and parcelled, Junior refused. Finally, the State of Nevada forced him to transfer land to the state, but by that time the state had decided to use the land as a state wilderness, thus preserving the area from development. The delay and prohibition of development prevented increased run-off, erosion and light pollution at Lake Tahoe, thereby preserving its clarity.
In the ATL without Junior's participation in the land purchase of the eastern side of Lake Tahoe, the back-East financier's withdrawal from the land purchase is fatal to the two partners who received an offer from Wittell in OTL. These two men then sell the land to other developers, rather than Wittell preventing development prior to environmental consciousness. The ecology of Lake Tahoe suffers far greater damage than in OTL, particularly in its clarity and light pollution. Twenty miles of casinos line the eastern shore.
1930s, early: George Whittell Jr. moves to Reno and founds a Nevada-based business to manage investments without paying California estate and income taxes. He buys land which will eventually encompass 40,000 acres and 27 miles of the Nevada shore of Lake Tahoe. He plans to build casinos at Sand Harbor and Zephyr Cove after he builds his own pleasure lodge. 1937: Construction of Whittell Jr.'s Thunderbird Lodge begins. 1939: The Thunderbird Lodge is completed. c. 1943: Whittell Jr. is growing more reclusive. He gradually abandons his casino plans in favor of his own private shore. 1944+: Whittell Jr. retreats from society. He lives in the summer with Bill the lion, Mingo the elephant, and forty birds (mostly mynahs) and invites only a few people to Thunderbird Lodge, including Ty Cobb and Howard Hughes.
1954+: Whittell Jr. suffers a broken leg when one of his lions falls on him. 1969 (April 18): George Whittell Jr. dies. His money goes to animal rights organizations. His lands (those which Nevada had not already taken) become public lands.