The San Gabriel Mountains begin north and east of the city of Los Angeles and range for over 60 miles, reaching a height of just over 10,000 feet at their highest point, Mt. San Antonio (better known as Mt. Baldy). Living in L.A. I often come across images taken on Mt. Wilson — the nearest large peak to the city and home to an Observatory as early as 1908 — and in the various nearby canyons, which have long attracted hikers. This circa 1908 shot shows one well-dressed group, and also has a rather charming approach to its border that I have not seen very often.
The San Gabriel Mountains are still quite rugged if you venture far enough into them, and are notable for remaining geologically active: they actually are said to be growing at a rate of 2 inches per year. As Wikipedia points out, “various faults crisscross the range, making it one of the steepest and fastest-growing ranges in the world. Plate tectonic activity breaks up most rock, making it unsuitable for rock climbing.”
Indeed, an interesting article on the history of the mountains on local public TV station KCET’s website observes that “although they don’t soar as high as the Sierra Nevada nor offer the same diversity of flora and fauna, the San Gabriels’ steep escarpments and deep ravines can challenge experienced adventurers. Even such a tireless trekker as John Muir met his match in the mountains. After an 1877 hike above Eaton Canyon, Muir described the San Gabriels as the place where ‘Mother Nature is most ruggedly, thornily savage.’ Chaparral provided the greatest nuisance — the prickly brush reduced Muir to crawling on his hands and knees for at least a mile — but the rugged terrain also merited a complaint. ‘The slopes are exceptionally steep and insecure to the foot of the explorer, however great his strength or skill may be,’ he wrote.”
Given the way the group in the photo is dressed, one can only assume they avoided sampling too much of that aspect of the mountains.