Shingle with reinforced nail zone and method of manufacturing

A roofing shingle comprising:

• an overlay sheet including a mat and an asphalt coating applied to the mat, and defining an upper headlap portion and a lower tab portion;
• an underlay sheet including a mat and an asphalt coating applied to the mat, the underlay sheet being secured to the overlay sheet such that a region of the underlay sheet overlaps a region of the headlap portion of the overlay sheet;
• and
• a reinforcement material secured directly to the asphalt coating of the headlap portion of the overlay sheet without extending into the tab portion to provide a reinforced nail zone that extends along a longitudinal axis of the shingle, wherein the reinforcement material is configured to improve nail pull-through, with the reinforcement material and the headlap portion providing a nail pull-through value that is greater than an otherwise identical shingle having no such reinforcement material;
• wherein the shingle further includes a granular material secured to the headlap portion of the overlay sheet, with no granular material adhered to the reinforcement material;
• wherein the headlap portion of the overlay sheet includes a depressed surface extending along said longitudinal axis of the shingle;
• and
• wherein the granular material secured to the headlap portion of the overlay sheet comprises a first granular material secured to a first portion of a front surface of the headlap portion of the overlay sheet, and a second granular material secured to a second portion of the front surface of the headlap portion of the overlay sheet adjacent to the first portion of the front surface of the headlap portion, with the first granular material providing a thinner cross-section than the second granular material to define the depressed surface.