FRAGMENTS OF SCIENCE. 



141 



eral, the nature and office of the secretions, 

 the nervous system, and the workings of 

 the brain — concerning which, "if increasing 

 knowledge gives us increasing power so to 

 mold a muscular fiber that it shall play to 

 the best the part which it has to ply in life, 

 the little knowledge we at present possess 

 gives us at least as much confidence in a 

 coming far greater power over the nerve 

 cell." 



The Tilting of the Lake Region.— The 



discussion of the geological history and fu- 

 ture of the region of the Great Lakes was 

 again brought up in the American Associa- 

 tion by Dr. W. J. Spencer, who, after review- 

 ing his investigations in former years of the 

 ancient outlets of Lake Erie, spoke of the 

 lake region as having been covered subse- 

 quently to the Glacial period by great bodies 

 of water all at one level. One of these, 

 Warren Gulf, which covered the lake basins, 

 was broken up by the rise of the land, and 

 Lakes Superior, Huron, and Michigan were 

 formed, their water emptying to the north- 

 eastward and not into the Erie basin. Af- 

 terward the land rose higher to the north- 

 eastward, filled the rivers of the basins 

 upward, and turned the upper lakes into 

 Lake Erie. At the same time the rocky 

 barriers caused Lake Erie to drown the 

 western hundred miles of its basin, and the 

 waters are now rising and will in a few cen- 

 turies cover Toledo and Detroit. The evi- 

 dence is recorded in the shore lines, which 

 have been surveyed by Professor Gilbert, 

 the author, and others. They have risen in 

 some cases from four to seven feet per mile 

 going northeastward in a period of about 

 fifty years. Prof. G. K. Gilbert in another 

 paper presented a comparison of surveys 

 made on the lake shores twenty or more 

 years ago and within the past year. It is 

 found that changes have taken place, all of 

 which show a rising of the land at the north 

 or northeast as compared with the land at 

 the south or southwest. The whole lake 

 region appears to be undergoing a tilting 

 toward the south southwest at such a rate 

 that of two points a hundred miles apart, 

 the northern rises five inches in a century as 

 compared with the southern. The mean 

 level of the lake rises at Chicago about an 

 inch in ten years, or ten inches in a century. 



It is estimated that in about three thousand 

 years all the overflow from the upper lakes 

 will go to the Illinois. The Detroit and St. 

 Clair Rivers will carry water from Lake Erie 

 to Lake Huron instead of from Huron to 

 Erie, and the Niagara River will run dry. 



Canada's Oldest Geology. — The presiden- 

 tial address of Dr. D. M. Dawson before the 

 Geological Section of the British Association 

 comprised a comprehensive but highly tech- 

 nical account of the Pre Cambrian Rocks of 

 Canada. At the close of his review the au- 

 thor said that the general tendency of our 

 advance in knowledge appears to be in the 

 direction of extending the range of the Palaso- 

 zoic downward, whether under the old name 

 Cambrian or under some other name applied 

 to a new system defined, or likely to be de- 

 fined, by a characteristic fauna. The some- 

 what arbitrary and artificial definition of the 

 Olenellus zone as the base of the Cambrian 

 seems to be not of world-wide application, 

 and not even generally appropriate to North 

 America ; while as a base for the Palaeozoic 

 eon it is of still more doubtful value. In the 

 Cambrian period as well as in much later 

 geological times the American continent does 

 not admit of treatment as a single province, 

 but is to be regarded rather as a conti- 

 nental barrier between two great oceanic 

 depressions, each more or less completely 

 diffeient and self-contained in conditions 

 and history — that of the Atlantic and that 

 of the Pacific. On the Atlantic side the 

 Olenellus zone is a fairly well-marked base 

 for the Cambrian ; on that of the Pacific it 

 is found naturally to succeed a great con- 

 secutive and conformable series of sediments, 

 of which the more ancient fauna is now only 

 beginning to be known. 



The Thumb and Toes in Men and Apes. 



— The presidential address of Sir William 

 Turner before the Anthropological Section 

 of the British Association was devoted to 

 some of the characteristics of human struc- 

 ture distinguishing it from that of the apes. 

 Its language is largely technical. The descrip- 

 tion of the differences in the disposition of 

 the thumb and of the toes presents many 

 points of interest. Both in man and the ape 

 the thumb is not tied to the index digit by 

 an intermediate ligament, which, under the 



