Unknown connection to digital counter 4060
The triangle indicates a logic inversion on the input.

The symbol for the part uses a convention that was invented 20 or so years ago (30?), and was intended to show, on the symbol, all you needed to know about the part. Where there are multiple logical functions in the part, these are split apart and shown separately.

In the case of the 4060, it has both an RC oscillator, and a binary counter. The oscillator is shown separately inside its own little box.

Pin 12, the Master Reset, operates to both clear the counter AND to disable the oscillator. The oscillator runs when the reset is low. The convention is that enables are shown in positive logic, so an inverter is shown on that input. As the input goes to two functions, it's shown as two inputs. Helpfully, one doesn't have a pin number on it, to show it's not a real input.

Why don't we see more of this type of diagram? The convention never really caught on, but it is still used. To show diagrammatically all the complexity of some circuits resulted in a few new squiggles being invented, and then combined in difficult to parse ways. Everybody, as soon as they saw one of these symbols, would just head to the data sheet to read what it did. It was an unnecessary complication, and not up to the job. VHDL for design of FPGAs was catching on at the same time, and was far more appropriate for complicated stuff, and simple logic stayed with simple symbols (mostly!).