Although much has been written upon the palæontology of the Suffolk box-stones, no description appears hitherto to have been published of the petrology of these boulders. This is the more curious on account of the light it might throw upon the disputed question of their source, no similar sandstone having yet been recognized with certainty in situ. The most recent account of the molluscan fauna is by my friend Mr. Alfred Bell. In a preliminary paper he has given a list of sixty-three species (excluding cetacean bones, teeth, crustaceans, etc.), about twelve new species and varieties being described. Mr. Bell has now kindly let me see in advance the MS. of a revised list of Mollusca (seventy-six species), much new box-stone material having been obtained in the last few years. As a result of recent work, he considers the affinities of the fauna to be rather with the Rupelian (Continental Oligocene) than with the Bolderian or Diestian, as he formerly thought. Mr. Clement Reid, in The Pliocene Deposits of Britain (Mem. Geol. Survey, 1890), considered the box-stones to be of about the same age as the Diestian Beds, but Mr. F. W. Harmer has, in later publications, been inclined to consider them to be rather older and of very early Pliocene age.