260 



SCIENCE. 



[N. S. Vol. XVI. No. 398. 



boniferous as they exist in the Appalachian 

 basin; the effort is made to determine the 

 boundary between Devonian and Car- 

 boniferous and to ascertain the changes in 

 physical geography during the period. 



A Neiv Meteorite from. Algoma, Kewaunee 

 County, Wisconsin: William Heebeet 



HOBBS. 



The Algoma meteorite, which was plow- 

 ed up near Algoma, Wis., in 1887, was rec- 

 ognized in March of the present year as a 

 true meteorite. It is almost unique among 

 meteorites because of its peculiar shape and 

 surface markings. Whereas most meteor- 

 ites are quite irregular in form, this me- 

 teorite is in the shape of a thin shield, or 

 disk, with convex and concave sides. Con- 

 trary to common notions it is quite clear 

 that this body, when it entered the atmos- 

 phere of the earth, presented its convex 

 surface to the front, and was in part by the 

 erosion of the air given its present form, 

 and its convex surface was deeply eroded. 

 From a central, smooth, elliptical area upon 

 the front, radial and slightly spiral groov- 

 ings proceed to the circumference of the 

 meteorite. It seems clear that these groov- 

 ings and ridges are the result of fusion 

 and erosion by the compressed air, the 

 dead-air area in front of the center pre- 

 venting a similar grooving there. 



Although not generally appreciated, it 

 appears that there have been other disk- 

 like meteorites, and from the principles of 

 mechanics it is clear that they, like the 

 Algoma meteorite, must have moved 

 through the atmosphere with their broad 

 side on. 



The Algoma meteorite shows well the 

 Widmanstatten figures produced by etch- 

 ing, and also numerous crystals of sehreib- 

 ersite. 



The Meteorites of Northwestern Kansas. 

 Olivee C. Faekington. 



Of the thirteen meteorites known from 

 Kansas, six have been found within an 

 area 115 miles long by 85 miles broad in 

 the northwestern part of the State. As 

 these all resemble each other in outward 

 appearance the question has been raised as 

 to whether they belong to a single fall. In 

 deciding the question the probable course 

 of a meteor and the structure and compo- 

 sition of the meteorites should be dis- 

 cussed. It is shown that the probable 

 course of the meteor would have been from 

 southeast to northwest, and not from south- 

 west to northeast as would be required if 

 the meteorites belonged to a single fall. As 

 regards structure and composition, three of 

 the meteorites have been studied, while the 

 other three have not. Results of studies of 

 two of the latter, Long Island and Frank- 

 linville, are given and the Long Island me- 

 teorite shown to be, in several respects, re- 

 markable. The conclusion is reached that 

 two of the meteorites may belong to one 

 fall but that the others are single individ- 

 ual falls. 



The Mohokea Caldera on Hawaii: C. H. 



Hitchcock. 



The eruptions from Mauna Loa upon the 

 southwest side are different from those 

 upon the northeast, chieiiy in being of the 

 explosive type. The new map of Hawaii 

 develops the interesting facts of the exist- 

 ence of an immense depression analogous 

 to a caldera a few miles back from Punu- 

 luu. It is of larger dimensions than the 

 celebrated ealderas of Mauna Loa and 

 Kilauea. 



Ellipsoidal Structure in the pre-Cambrian 

 Basic and Intermediate Backs of the 

 Lake Superior Region: J. Moegan 

 Clements. 

 The greenstones of pre-Cambrian age in 



the Lake Superior region have very com- 



