Personal and Scientific Nezvs. 399 
For over 25 years he spent nearly all his leisure in studying 
the rocks of central Missouri, particularly the beds of the Bur- 
lington and the Chouteau limestone. He made a large col- 
lection of fossils, but generously gave them away. His cous- 
in, Sam Aliller of Cincinnati, Ohio, described and jfigurcd 
many of the fossils found by Mr. Blair. He was a good 
collector and probably collected more Chouteau fossils than 
anyone else. He was a member of the State Board of Mines 
and Geology from 1889-1890. His wife died in 1901. He 
leaves one daughter, Miss Jessie Blair. g. c. broadhead. 
Professor W. H. Hobbs recently presented (Oct. 20) a 
paper to the New York Academy of Sciences which was ac- 
companied by a wealth of detailed observations on the geol- 
ogy of Manhattan island, condensed as follows by the secre- 
tary, Dr. E. O. Hovey : 
in his introduction the author called attention to the unusual oppor- 
tunities now offered for studying the geology of Manhattan island 
through the numerous great engineering projects now being carried 
forward. The waterways surrounding Mauihattan island are deep caii- 
ons, with a depth of nearly 200 feet in the East river and 300 feet or 
more in the North river, now partly filled with drift deposits the 
amount depending o.t the velocity of the tidal currents. 
In 1865 Stevens advanced the theory that the river channels were 
along lines of faults ("longitudinal and transverse fractures"). New- 
berry regarded the East river as the lowest reach of the Housatonic 
river before it discharged its waters into the Hudson, which was then 
the outlet of the Laurentian series of lakes, and he considered the 
Harlem river with Spuyten Duyvil creek a smaller tributary of the 
Hudson- 
Dana believed that the relatively easy solution of certain beds of 
limestone determined the position of the river channels. This view of 
Dana's has bee.T. supported by Kemp and Merrill, while Gratacap re- 
jects the theory advanced by Stevens. 
Professor Hobbs finds that no correspondence can be established 
between the directions of the belts of limestone or dolomyte and of the 
New York water front, except within the stretch from Kingsbridge 
to Macomb's Dam bridge. Along this line too the observed facts 
- point to the occurrence of a narrow strip of limestone dropped down 
between nearly vertical faults. The sections of the Harlem river which 
are furnished by the bridges across it show clearly that it is not a sim- 
ple erosion valley resulting from cutting by the stream. The bed of 
the stream is marked by sudden changes of level, and the Harlem 
seems to have chosen its course quite independently of the position of 
ridges of the harder gneiss. Under the East river limestone has been 
found at but two localities. — under the chan-nel east of Blackwcll's 
island and in one of the drill holes underneath the Manhattan pier of 
