Ronald Searle is mostly a pen and ink guy, with the occasional wash of color/tones. Think 101 Dalmations and Jay Ward is the mastermind behind Rocky and Bullwinkle.
Here are some samples pieces:
As you can see, both artist have a very different aesthetic. Here is my stab at the design challenge. I drew a chicken dragon since birds are the descendants of the great Dinosaurs. Dragons are basically winged-dinosaurs (besides the pteradactyl). Ward on the left and Searle on the right.