RIVERSIDE (AP).- A utility company preparing to build a new substation in an arid canyon southeast of Los Angeles has stumbled on a trove of animal fossils dating back 1.4 million years that researchers say will fill in blanks in Southern California’s history. The well-preserved cache contains nearly 1,500 bone fragments, including a giant cat that was the ancestor of the saber-toothed tiger, ground sloths the size of a modern-day grizzly bear, two types of camels and more than 1,200 bones from small rodents. Other finds include a new species of deer, horse and possibly llama, researchers affiliated with the project said. Workers doing grading for the substation also uncovered signs of plant life that indicate birch, pine, sycamore, marsh reeds and oak trees once grew in the area that is now dry and sparsely vegetated. The fossils representing 35 species have all been removed from