The picture you have is a picture of an oscillator, which is different from the crystal in the schematic. A crystal is component inside
an oscillator circuit; the oscillator shown is a device that contains a crystal and other circuitry that will produce a square wave when power is applied. On devices that just require a crystal (and usually some caps), like the tone decoder or a PIC, there is additional circuitry inside the device that completes the oscillator circuit, and that external circuitry expects a crystal, not a clock input from an oscillator.
So, in general, you can't sub an oscillator in place of a crystal. In PICs and other microcontrollers, you have to change the configuration to accept a fully formed clock input from an oscillator as opposed to a crystal.
But for this chip, looking at page 4-15 of the spec
, it looks like you can just apply the output of an oscillator to the OSC1 input. Attaching ground to the OSC2 will most likely not work at all. Just leave OSC2 disconnected. The spec also says you need a 3.579545 MHz clock / crystal, so it probably won't work if your oscillator is at a different frequency.
Our crystal page
explains a bit of the difference between crystals and oscillators, as well as their tradeoffs, and maxim has an even more in depth explantion
Hopefully I'm answering the right question, and you didn't already know all that.