Complex sentence: On August 28,1769, the Portola expedition camped near Point Arguello, where they found a small Indian rancheria, the locale of which abounded in excellent flints, whence they named it Los Pederales (The Flints).
Split into simpler sentences: On August 28,1769, the Portola expedition camped near Point Arguello, where they found a small Indian rancheria. This area had many excellent flints, and so they named it Los Pederales (The Flints).