In the collection of Mr. Alfred Brown, of Ariwal North, which I had recently the pleasure of looking over, I came across the right lower jaw of a small mammal which Mr. Brown had discovered in sandstone near Ariwal. Though unfortunately the teeth are lost, there is evidence of there having been a large canine. The most remarkable character of the jaw is its extreme shortness, and in its general proportions it agrees much more with the jaws of some of the small carnivorous Eutherians than with those of the small carnivorous or insectivorous genera already known from the Secondary rocks. The angle is well developed and but very slightly inflected. The condyle is practically in a line with the alveolar margin.