California Split: Ten California members of Congress have endorsed former vice president Walter F. Mondale for the Democratic presidential nomination, dealing a jolt to the campaign of their fellow Californian, Sen. Alan Cranston.

Cranston is banking on picking up most of the state's delegate votes at the Democratic National Convention in July, 1984.

In a letter to Mondale Thursday, the House members wrote, "We believe you are uniquely equipped and prepared to deal effectively with the difficult problems the next president must face. We also believe that you are able to unite the Democratic Party, to lead us to victory in 1984 and then to lead the American people toward the realization of those goals."

The 10 signers were Reps. Jim Bates, Douglas H. Bosco, Mervyn M. Dymally, Robert T. Matsui, Leon E. Panetta, Anthony C. Beilenson, Barbara Boxer, Vic Fazio, Norman Y. Mineta and Fortney H. (Pete) Stark Jr.

A spokesman for Cranston's campaign said the senator has the support of California Reps. Glenn M. Anderson, Howard L. Berman, George E. Brown Jr., Don Edwards, Tom Lantos, Mel Levine, Matthew G. Martinez, George Miller, Jerry M. Patterson, Edward R. Roybal, Esteban E. Torres and Henry A. Waxman. The spokesman said Cranston is supported by a majority of the Democratic members of the state's assembly and senate.