Complex sentence: In 1859 while in Los Angeles, Holcomb and a companion Jack Martin, heard of the Bear Valley diggings near San Bernardino and set out to make another try at mining there.
Split into simpler sentences: In 1859 while in Los Angeles, Holcomb and a companion Jack Martin heard of the Bear Valley diggings near San Bernardino. They set out to to make another try at mining there.