An example of a typical NATCO hollow clay tile as advertised in their 1910 catalogue.  "The visible points of superiority, as compared with similar tile of different makes, are the deep dovetail scoring for the better bonding of stucco or plaster, the absence of imperfections and the better general symmetry due to the more accurate machining by this company's unequaled equipment. Equally important qualities not obtainable in other tile are not so apparent to the eye. These consist of finer properties in the raw clay and its more uniform and thorough burning, resulting in greater density and a higher degree of inherent strength. It is to certify these advantages, and to instantly identify the tile possessing them, that the name NATCO is stamped plainly upon the face of each tile." —From NATCO Catalog "Fireproof Construction for Houses and Other Buildings at Moderate Cost," 1910.