detecting lisp overflow



If I call adaptive-plot (plot.lisp) appropriately with 
a function like exp(x^3) to see what overflow
causes adaptive-plot to return, I get, for example,
the lisp list

(100.0 #<1.#INF00e+000> 100.24245689655172 #<1.#INF00e+000>
           100.48491379310344 #<1.#INF00e+000> 100.72737068965517
           #<1.#INF00e+000> 100.96982758620689 #<1.#INF00e+000> .....  )

I want to detect that this result is not a list of floating point numbers.

If I use either:

       (numberp  #<1.#INF00e+000> )

or

      ($numberp  #<1.#INF00e+000> )

I get a lisp error.

Is there some other way to detect this type of output?

Ted Woollett