Journal of Proceedings. xvii find.* And finally he wished to know whether Mr. Smith had noticed any relationship showing a sequence in time of the river-gravels when compared with the glacial gravels in their district. Mr. Robarts said he felt sure he spoke the feelings of every member in saying how much they were obliged to Mr. Smith for his admirable paper, which had given them a great deal of information about what had occurred in their own neighbourhood. He should like to ask one or two questions with regard to the hammer-stones. He wished to know whether Mr. Smith had found these to be made of many kinds of stones, or whether they were chiefly of quartzite—whether he had been able to trace that one particular stone was better adapted for making implements than another. Also, with regard to the three ages to which Mr. Smith had referred, and the smaller and more finished implements which were made in the latter period, whether the size of the implements was any indication of the date—whether the very largest implements were all of the very oldest date, or whether any of the very large implements were found in the latest age ; in fact, whether the gravel contained such large stones at the latest dates as it did at the earlier dates. Mr. Robarts also alluded to the perfection of form shown in some of the Neolithic celts, and expressed an opinion that they were really finer than some of the best axes we had now; that was to say, the curves were more beautiful, though the imple- ments were not perhaps so well adapted for cutting. Mr. Smith, in replying, placed implements of the three ages side by side, and held that they furnished conclusive evidence of a marked improvement in the manufacture, and therefore in the status of the men who made them. He was not able to give an immediate and short answer to Mr. Meldola's question as to the rate of denudation of river valleys ; the subject was a large and intricate one, and a whole evening would hardly suffice for its discussion. He next referred to the question raised by reference to Mr. Skertchley's discovery, and said he had unfortunately seen none of Mr. Skertchley's sections, and so could give no opinion from his own observation. Opinions were very much divided as to the age of the material in which Mr. Skertehley had found the so-termed glacial implements. Mr. Smith had found implements in gravel said to be middle-glacial at Amwell, Ware, and Hertford, but some geologists questioned the age of these deposits. The "hammer-stones" were nearly always of quartzite; he had only two examples made of another stone: both were of flint; one a rudely cylindrical nodule, the other a fossil cast from the Upper Chalk—an Echinite (Ananchytes ovatus) ;—this had been "found" by a palaeolithic man and used as a hammer-stone, and a flake detached by repeated hammering. As to the sizes, he was sorry to say that size was not an invariable test of the age of an implement, * See Prof. Ramsay's ' Physical Geology and Geography of Great Britain,' pp. 481 and 544; Prof. Boyd Dawkins' 'Early Man in Britain,' p. 169, note (1880); 'The Fenland, past and present,' by S. H. Miller and Sydney B. J. Skertehley, p. 546 (1878); and Proc Essex Field Club, vol. ii., p. xxiv.—Ed. b