Gunnite

Gunnite (or Gunite), is mortar conveyed through a hose and pneumatically projected at high velocity onto a surface.  (Mortar is a sticky cement/sand/water, and usually lime, mixture designed to adhere.)

The force of application and "peening effect" of the larger particles results in a very dense, waterproof mass. 

 

Trademarked in 1909, the form-less process gained popularity amongst architects in part for its resemblance to the rough pebble dash finishes of England: crushed rock set into an outer coat.

While "shotcrete" has become the all-inclusive term for sprayed or "gunned" concrete, several processes exist, and gunnite refers to a specific dry-mix technique.

The finish, typically a pale grey, was usually left unpainted.  

As styles changed, many examples were foolishly stuccoed, and are subsequently disguised, made more adobe-like, or smooth coated like this work by architect Charles Whittlesey.  Deformed.