Yet, broad and extensive as these improvements and enlargements of the original peninsula have been, they are at least equalled, if not exceeded, by what has been accomplished in other parts of the town; so that Boston proper--at first two islands, or nearly so, and afterwards a peninsula--has long ceased to be either the one or the other, and must now be regarded as a portion of the mainland. And this, too, while Charles River, by encroachments upon its bed on both sides, the numerous wharves projecting into it, and the bridges, railroads, and other structures resting upon its bottom, has been reduced in its proportions to one-third of its original size, and, in fact, has almost ceased to be a river in the proper sense of that term. So also on the south side of the town: Four Point Channel, which reached to Dover-street bridge, is now a narrow stream; and the South Bay, which lay between Roxbury and South Boston, has been greatly reduced in its proportions, and is crossed by the New England Railroad. So that it may be said, the city proper to-day stands consolidated on one side of the ancient neck with Roxbury and Dorchester, and on the other with Roxbury and Brookline. There still remain, however, a section of Charles River, forming a bay of itself, between Boston, Cambridge, and Brookline, and a considerable portion of the South Bay between Roxbury and South Boston. Brookline--originally Muddy Brook--was formerly considered as belonging to Boston, and its lands were apportioned among the early settlers of the town for agricultural purposes and the keeping of cattle. It is now nearly surrounded by the enlarged city, Brighton and Roxbury both belonging to Boston. There is, however, one feature of Boston which may be said to remain intact, and that is BOSTON COMMON. When the settlers bought the peninsula of William Blackstone, or all his interest in it, excepting six acres, which he reserved for his own occupation, "the town laid out a place for a training-field, which ever since and now is used for that purpose, and for the feeding of cattle." This was undoubtedly the origin of Boston Common; and the date of the transaction, as appears from the town records, was on "the 10th daye of the 9th month, 1634," which, as the year commenced with March, would be November, 1634. It has undergone many changes, some enlargement by filling up the marsh on the river side, and numerous improvements in its general appearance by laying out its malls and walks, setting out trees, excluding cattle, walling around Crescent Pond (formerly Frog Pond), introduction of the Cochituate water and fountains, and, last, by the erection of the Army and Navy Monument on its highest elevation, once occupied as a fortification against its rightful owners by Gen. Gage and Gen. Howe.