310 Scientific Intelligence. 
Survey. The mean height of Lake Erie was arrived at by means 
of levelings (1) on the Erie Canal from Albany to Buffalo; (2) 
f : : 
the North sents Pennsylvania Bed. § r ) by the Erie R 
R. to Dunkirk and Cleveland; (6) by the Canadian Grand Trank 
hk. R. The results obtained by these six routes respectively are the 
following: 573°08, 572°037, 572°670, 570°750, [581°20], 571°67 feet. 
This example illustrates the method used for obtaining the true 
elevation, and shows also the high degree of confidence that may 
be placed in them; and further that Mr. Gardner makes in his 
memoir a contribution to North American topography of extreme 
speporiane 
A few a of the heights ascertained are: Quebec, mean tide 
level, 15°37 feet; Montreal, summer water-level, 30 feet; Lake 
Champlain, mean level at Whitehall, 100-84; Pittsburg, Ba, low 
water in river, 699°20; Louisville, Ky., ow water above Falls, 
about 404; New Albany, Ind., low water in 1857, 379°75, and the 
depot of Led Asd.G. B. R.; 451° ans ce Island, Ul. phigh water 
in Mississippi in 1852, 566- 68 ; Terre Hau e, Ind., high water in 
Wabash, 485°55, a" ordinary water, 467 we ; "Mount Lincoln, ee, 
orado, 14,296° 66 
2. Geological c pact y of Canada, Av¥rep R. m SEL nee gi 
ort of Progress for the year 1873-4. 268 pp. 8vo. 
8.) 
(D 
_ on this side of the Atlantic exceed in value those of the 
Canada Geological Survey. The volume recently issued contains, 
besides an introductory report of 16 pages by Mr. SELWYN, obser- 
vations in the Northwest fess from Fort ¢ sary to k 
Mountain House, by the same; Report on the country between 
Red Rive er a and the South Saskats ‘hewan, with notes on the — 
Mr. James Ricnhirpson; Report on explorations and surveys 10 
Frontenac, Leeds and Lanark ae iia notes on the sere of 
4 e coal series, by Mr. J. F. Wurreaves. A on 
Billings on fossils from Gaspé and another by Mr. on are e in 
sli a ss; and a a Report by Prof. Bailey and Mr, Ells, on New 
runswick Geology. 
Selwyn we a in his Introduction, that the facts gathered 
Send oe prove that lithology among crystalline e rocks is not a sa 
test of geological age, observing that this conclusion is favored b 
the recent researches of Mr. ee do seg in British Columbia, which 
