SCIENCE. 



193 



other hand, no such flood as deposited this gravel has ever 

 occurred within the historical epoch. No such large bould- 

 ers are ever now carried down the river. No modern rain- 

 storms could cause such a flood. It is difficult to assign 

 any other cause than that of a melting glacier. Yet such a 

 glacier could hardly be the great Northern glacier, for these 

 gravels are much newer than those of the Champlain epoch. 

 There is here evidence of a second and more recent glacier 

 in the Delaware valley. 



The hypothesis of a second glacial epoch seems to explain 

 all the facts observed. A similar period in Europe — the 

 reindeer period — is supported by many facts. Should such 

 a period not be traced in America, the date of the melting 

 glacier must be made much more recent than that generally 

 assigned. 



The relics of man which occur in the Trenton gravel, 

 and which were first found by Dr. C. C. Abbott, arc of 

 great interest. In shape, in size, in workmanship, and in 

 material the implements here found are quite different from 

 those used by the Red Indian. These " palaeoliths " are 

 imbedded at various depths in undisturbed Trenton gravel. 

 There are two points which offer strong evidence that the)' are 

 as old as the gravel. The first is the fact that modern Indian 

 implements (" neoliths "), although abundant on the sur- 

 face, never occur more than a few inches below it, and are 

 never associated with the palaeoliths, which are found at 

 depths of from five to forty feet below the surface. This 

 fact alone argues a different age for the two classes of im- 

 plements. The second fact is that, when found below the 

 surface, the palaeoliths always occur in the Trenton gravel 

 and never in older gravels. The writer has gone over, with 

 Dr. Abbott, much of the ground where the implements 

 occur, and it was very interesting to find that it was only 

 within the limits of the Trenton gravel, previously traced 

 out by the writer, that Dr. Abbot had found implements 

 below the surface. Here, then, is the strongest probability, 

 even if the implements were found on the surface only, 

 that they belonged to and were of co-eval deposition with 

 the river gravel. 



The implements found in the river gravels of Europe are 

 of similar type, though as a rule perhaps less rude. It is 

 of interest to find that very similar implements have been 

 used by the Eskimos, and it is probable that that race, now 

 living in a climate and under conditions perhaps similar to 

 those once existing in the Delaware, may have some kinship 

 with the pre-Indian people of this river. The occurrence 

 of bones of arctic animals in the Trenton gravel indicates 

 a period of cold. 



All the evidence now gathered points to the fact that at 

 the time of the Trenton gravel flood, man, in a rude state, 

 lived upon the ancient banks of the Delaware. If future 

 archaeological work can show a connection between this 

 people and the Eskimos, it may be appropriate to call the 

 period of the Trenton gravel and of this palaeolithic people 

 — a period perhaps following a second glacial age — the 

 Eskimo period, a name more suggestive, and derived from a 

 higher order of beings than that which gave the name 

 " Reindeer Period." 



While others have held that the occurrence of imple- 

 ments in the Trenton gravel indicates the existence of man 

 in inter-glacial or even pre-glacial times, the writer believes 

 that the investigations here described indicate the origin of 

 man, at a time which geologically considered, is recent. 

 Neither in the Champlain deposits, in the morainic material 

 of the north, or in any older gravels have undoubted traces 

 of man been discovered. 



The actual age of the Trenton gravel, and the consequent 

 antiquity of man in the Delaware, cannot be determined by 

 geological data alone. It is the aim of this paper to define 

 man's antiquity in relation to geological rather than to his- 

 torical events. If, in showing that the Eskimo period is 

 the last of the geological ages, it docs not necessarily fol- 

 low that it is by any means recent ; it must be remembered, 

 on the other hand, that its high antiquity is not proven by 

 the facts thus far observed. 



The conclusions to which the facts seem to point are 

 briefly summarized as follows : 



r. That the Trenton gravel, the only gravel in which im- 

 plements occur, is a true river deposit of post-glacial age, 

 and the most recent of all the gravels of the Delaware 

 valley. 



2. That the palaeoliths found in it really belong to and 

 are a part of the gravel, and that they indicate the existence 

 of man in a rude state at a time when the flooded river 

 flowed on top of this gravel. 



3. That the data obtained does not necessarily prove, 

 geologically considered, a vast antiquity of man in Eastern 

 America. 



PYROLOGY, AND MICROSCOPICAL CHEM- 

 ISTRY. 

 By W. A. Ross, Lt. Colonel, late R. A. 



(1). In the year 1869, at Simla, India, having applied a 

 trace of oxide of cobalt to a bead of boric acid before the 

 blowpipe, I observed that, instead of dissolving, as I had 

 been led to expect, small round black spots were formed, 

 which, appearing perfectly round through the clear bead 

 from every point of view, seemed to be spherides or balls. 

 It was afterwards found that 14 oxides form such balls in 

 boric acid, B. B., among which the most useful pyrological 

 was that of calcium. 



(2). I found, by the average of five assays, that the weight 

 of the calcium borate ball, extracted by boiling water in 

 which it is utterly insoluble, while the containing bead is 

 rapidly dissolved — was a constant nuiltiple of the weight of 

 the calcined lime taken to make it, and that this multiple 

 was 4.5. Thus, if w — the weight of the ball, the formula 

 —_ represented the quantity of pure lime in it. If calcium 



hydrate was taken, instead of calcined lime, a clear ball 

 was still formed within the bead, which latter became 

 opaque through opalescence, and as the balance showed 

 that this ball also contained the above mentioned propor- 

 tion of calcined lime, the opalescence was attributed to 

 chemical water. 



(3). Circumstances of a painful nature, which I need not 

 here relate, prevented my going further into this matter for 

 eight years, but I vainly solicited the Microscopical Society 

 to take it up, and having been enabled this year (about two 

 months ago) to purchase a binocular microscope, with 

 polariscopic apparatus attached, I fitted a small spectro- 

 scope I had by me into one of its eye-pieces with cotton 

 wool, etc., and renewed my examination of these boric 

 acid balls. 



TIN BORATE, (POLARIZED). 



(4). Notwithstanding the undoubtedly chemical nature of 

 the combination I have called "a calcium borate ball," the 

 phenomenon of ball formation itself is obviously as much 

 related to the subject of molecular physics as to chemistry, 

 and seems explainable briefly as follows : All liquids 

 having cohesion have, under circumstances of equilibrium, 



