I n two former papers communicated to the Geological Society I observed that certain large trifid bodies, presenting a resemblance to the casts of the impressions of birds′ feet, were numerous in the cliffs to the east and west of Hastings; and I suggested, from certain uniform peculiarities which these gigantic tridactyle impressions, or rather casts of impressions exhibited, that they might be really foot-marks of birds. Up to the date of my first notice, my discoveries of these colossal casts were limited to the east of Hastings and Bulverhithe, but my continued investigations enabled me to announce in my second communication that I had successfully traced them through the entire section of the Wealden rocks exposed on the coast, from Cliff's-end on the east of Hastings to Pevensey Sluice on the west. Although these tridactyle casts were collectively numerous, they occurred for the most part on detached blocks of sandstone, and never on a surface sufficiently large to admit of three or four consecutive marks; and, although their number and regularity of form afforded good presumptive evidence of their being organic in their origin, yet these circumstances were insufficient to establish a truth where sequence of arrangement, distinct evidence of a phalangeal structure, or some other organic characters were indispensable; hitherto, therefore, these trifid bodies were not supposed to fulfil the necessary conditions of footmarks . The uniformity of character, however, in the casts that I first examined had such an obvious connexion with a definite cause, as to convince me