It now becomes our duty, as faithful chroniclers, to point out the localities at present occupied by that class of the population, and tell the secret of their lives and how they exist. The region which most engrosses the attention of the police is that conspicuously known as "Mackerelville," which for some years past has borne rather an unsavory reputation. While there are many deserving and worthy persons dwelling in the locality, quite a different type of humanity also makes its home there. The neighborhood in question is comprised in Eleventh, Twelfth and Thirteenth streets, and First avenue, and Avenues A, B and C. It harbors a wild gang of lawbreakers, ready and willing to commit any kind of lawless act, in which the chances of escape are many and detection slight. Notwithstanding the decimation of its ranks by frequent and well-deserved trips to the penitentiary of its members, for every crime from murder down, it appears to survive, to the terror of the respectable poor living in the neighborhood and the constant dread of the police officer. It is a locality and a gang much dreaded at night, but not nearly so much now as formerly, for when a member commits a crime of any importance now he is invariably ferreted out, arrested and punished. The Tenth Avenue gang is a chance affair, owing its existence to the successful and bold express robbery occurring some years ago, but which is still fresh in the minds of most people from the skillful manner in which it was executed, and from the number of prominent rascals participating in it. The robbery referred to, at the time of its occurrence, was current talk, and continued a subject of conversation for many weeks afterwards. A number of ingenious, daring and highly-cultured train robbers, under the leadership of the notorious Ike Marsh, among whom was one who has since attained celebrity as an actor, boarded a train on the Hudson River Railroad, near Spuyten Duyvil, the spot immortalized by Washington Irving, and, entering the express car, bound and gagged the messenger in charge, threw the safe off and jumped after it. The iron box contained a large amount of greenbacks and government bonds, which the thieves succeeded in appropriating. Some of these daring robbers were subsequently arrested and lodged in the White Plains jail, but on the day set for the trial, the sheriff discovered that his prisoners of the night before, whom he imagined quite secure, had left, without waiting to say good-bye. Some friends and confederates came to their assistance, released them and drove them down to the city, from whence they finally reached our sister Kingdom, recently made famous as the abode of the fashionable defaulter.