To-day, the 7th of September, I made a discovery. The pair of red-birds that built in my cedar-trees last winter got duly away with the brood. Several times during summer rambles I cast my eye about, but they were not to be seen. Early this afternoon I struck out across the country towards a sinkhole in a field two miles away, some fifty yards in diameter, very deep, and enclosed by a fence. A series of these circular basins, at regular distances apart, runs across the country over there, suggesting the remains of ancient earth-works. The bottom had dropped out of this one, probably communicating with the many caves that are characteristic of this blue limestone.