Septemeeb 27, 1907] 



SCIENCE 



401 



of Section E, Dr. Alfred C. Lane, who gave 

 his vice-presidential address on the "Early 

 Surroundings of Ldfe."^ 



Professor B. K. Emerson thanked the 

 authorities of the Champlain Assembly for 

 their hospitable reception of Section E. 



On Sunday various features of the local 

 geology were visited by members of the 

 section. Others attended services at the 

 Chapel on the grounds. 



At noon the party were entertained most 

 delightfully by the Honorable Smith M. 

 Weed and his family at his summer home 

 on the shores of Lake Champlain. In the 

 afternoon another sail was taken in a steam 

 launch on Lake Champlain. 



In the evening Professor George H. 

 Hudson, of the Plattsburg Normal School, 

 showed the laboratories and some of the 

 work of his students. The members then 

 met in the science class-room, and listened 

 to an informal talk by Professor Hudson 

 on "Blastoidocrinus and its Type," illus- 

 trated by fifty lantern slides. The slides of 

 Billings's type were from negatives pos- 

 sessing an amplification of ten diameters, 

 and showed in a remarkable manner many 

 points of structure not before noted in the 

 specimen. The outer folds of the hydro- 

 spires were seen to extend under the inter- 

 brachials to the edges of the bibrachials. 

 The position of the stem was shown to be 

 not normal, as Billings supposed, but 

 thrust up into the coelomic cavity and 

 separating the basals from the radials. 

 There were no features to show a specific 

 difference between the Canadian type and 

 the more perfect Valeour island specimen, 

 but the type served to corroborate in a 

 clear manner much of the detail worked 

 out from the latter and published in Bul- 

 letin 107 of the New York State Museum. 



On Monday, July 8, the party went by 

 train from Plattsburg to Lyon Mountain, 



" Published in Science for August 2, pp. 129- 

 143. 



and spent the day studying the magnetite 

 mines under the guidance of Mr. Newland. 

 After lunch the section listened to a paper 

 by D. H. Newland on 



THE IRON OEES OF THE ADIRONDACK 

 REGION 



Four varieties of iron ores are found 

 within the limits of the Adirondack region, 

 each constituting a more or less inde- 

 pendent class of deposits as regards geo- 

 logical associations and mode of origin. 

 The varieties are as follows: (1) Non- 

 titaniferous magnetites, (2) titaniferous 

 magnetites, (3) hematites, (4) limonites. 

 In respect to the relative age or period of 

 formation, it is probable that the mag- 

 netites of class 1 are the oldest, since they 

 antedate the metamorphism and structural 

 disturbances that affected the region dur- 

 ing Precambric time. The titaniferous 

 ores were formed before the oldest of the 

 fossiliferous rocks of the region (the Pots- 

 dam sandstone) was deposited, and are 

 generally regarded to be contemporaneous 

 with the igneous inclusions in which they 

 occur. The hematite ores are probably 

 later than the Potsdam ; while the limonites 

 have the character of bog ores and are 

 relatively recent surface concentrations. 



The non-titaniferous magnetites .are the 

 most wide-spread of all the ores in their 

 geographical distribution, and have been in 

 the past and still are the main source of 

 supply for the region. In a strict sense 

 they are hardly deserving of the name that 

 has been applied to them by geologists, 

 since they nearly always carry titanium, 

 though the amount is small, usually but a 

 fraction of one per cent. These ores are 

 found in all parts of the Adirondacks, 

 except the central which is occupied by the 

 great gabbro-anorthosite mass. They are 

 associated with different members of the 

 Precambric crystalline series, including 

 gneisses of igneous derivation with the 



