92 The American Geologist. Febrnary, i89i« 
tailed examination further west, predicted the discovery of similar 
ores, a discovery actually made in 1866, by Eames, who was then 
state geologist, and engaged in studying the Vermilion range. Though 
not utilized at once, these announcements were not forgotten and 
systematic exploration was begun in 1875, when the need of high 
grad** ores at low prices made necessary the opening of new areas. 
Almost at once, the state geological survey determined the extent 
of the ore-bearing region, differentiated the deposits and removed 
erroneous impressions respecting the extent and distribution of the 
ores. The effect of these discussions and of the positive fixing of 
areas has been to increase development and to cheapen ores of the 
best quality so far that Bessemer steel can be manufactured more 
cheaply in the United States than elsewhere, in spite of the fact that 
wages are still higher, not simply numerically, but in purchasing pow- 
er, than in any other iron-producing country. An examination of 
the reports which have brought about this result compels one to say 
that the anxiety for economic results does not appear to have been 
an impelling motive during the work. There were perplexing geo- 
logical problems to be worked out and the solutions could be dis- 
covered only by the most painstaking work. This investigation led 
to the economic results and experience has shown over and over 
again, the value to the several states and to the nation at large aris- 
ing from geological surveys carried on by trained scientists. 
Aside front the two papers already noted there were forty- 
six communications laid before the society, of which number 
thirty-five were read. The first paper read was by AV. O. 
Crosby, of the Massachusetts Institute of Technology, and was 
entitled. "The Archean-Potsdam Contact in the Vicinity of 
Manitou. Colorado." By means of photographs and diagrams 
the author showed the remarkably plane character of the con- 
tact of the Archean granite and the Potsdam sandstone, which 
is in striking contrast with the existing topography of the 
granite even in coastal regions. 
The paper distinguished and described in detail with numerous il- 
lustrations the original and secondary irregularities of the contact, 
the latter including a few flexures and numerous small faults which 
throw important light upon the origin of the sandstone dikes of the 
Manitou district. The original irregularities of the contact are all 
small, and, as a rule, evidently related to the occurrence in the Arch- 
ean granite of a coarse concentric or spheroidal structure. The gen- 
eral conclusion of the paper was that the Archean land surface must 
have passed with extreme slowness beneath the waves of the Potsdam 
sea. 
' ' Outline of the geology of Hudson Bay and Strait. ' ' by Robert 
Bell of the Canadian geological survey. The author considers Hud- 
