Engelke Brothers Maker's Mark, 1919, Casper Wyoming.

I posted one of these the other day from the same company, in which the year, 1913, was also stamped in.  In this one, it was simply lined in by hand, for a much less professional appearance.  Oddly, this one is a few years younger.  It's also several blocks away, presumably representing the advancing sidewalks of the town in the teens.

Hedquist Construction Sidewalk Maker's Mark. Center Street, Casper Wyoming

Engelke Brothers Sidewalk Maker's Mark. 1913. Casper Wyoming.

It used to be the custom, and probably at least still partially is, for cement companies to stamp their names in their product.  this is an example of a Engelke Brothers mark, in downtown Casper, from 1913.

Many Casper sidewalks were of this vintage in the general downtown area, but in recent years the sidewalks have been torn out and replaced, so these really old stamps are not nearly as common as they once were.