Complex sentence: He described the range and habits of the large mammals of Yellowstone, and expressed regret for "the unfortunate breakage of my thermometer when it could not be replaced" but submitted a synopsis of the weather the previous winter.
Split into simpler sentences: He described the range and habits of the large mammals of Yellowstone. He expressed regret for "the unfortunate breakage of my thermometer when it could not be replaced" but submitted a synopsis of the weather the previous winter.