Oct., 1907. Meteorite Studies II — Farrington 125 



as shown in several of the plates. The crackle lias a mesh-like 

 pattern with meshes in the form of polygons, squares and triangles 

 from Y to yi inch on a side. The appearance is entirely similar 

 to that presented by crackled earthen ware and is doubtless produced 

 by shrinking of the crust in cooling, or expansion of the interior of the 

 meteorite subsequent to the formation of the crust. Another interest- 

 ing feature seen on the crust of several individuals is that of glazed 

 spots of occasional occurrence. The spots are usually of a greenish 

 color, oval to circular in area, and vary from Y ^° H mcn m diameter. 

 They doubtless mark the location of chondri of fusible composition. 

 Under the microscope the crust shows in cross section a thickness 

 of about .5 of a millimeter. The three zones of Tschermak are plainly 

 marked, with widths averaging as follows: Fusion zone .025 mm., 

 absorption zone .1 mm., impregnation zone .4 mm. These zones ex- 

 hibit the usual characters, the fusion zone being black, opaque and 

 glassy, the absorption zone transparent, and the impregnation zone 

 showing a large proportion of black, opaque matter. The relative 

 widths above given remain fairly constant, although in places the ab- 

 sorption and fusion zones are of about equal width, and again the 

 absorption zone may disappear altogether. The fusion zone is at 

 times also blebby and rough in outline. The interior of the meteorite 

 is megascopically ash-gray in color, in some individuals flecked with 

 rusty spots. The substance is only fairly coherent, and will not polish. 



PONCA CREEK. 



The writer proposes the name of Ponca Creek for the meteorite usu- 

 ally known as Dakota. The reasons for the change are as follows: 

 The original account by Jackson* states that the fragment which he 

 described was given him by the U. S. Indian agent for the Ponca tribe 

 of Indians, and further that the mass was found on the surface of the 

 ground "in the Dakota Indian territory, ninety miles from any road or 

 dwelling." In the repetition of this statement by foreign authorities 

 a comma came to be inserted after Dakota, so that the locality was 

 known as Dakota, Indian Territory. There is no such locality, how- 

 ever, and Indian Territory is several hundred miles removed from the 

 place where the meteorite was found. Moreover, the original territory 

 of Dakota, within which the meteorite may have been found, is now 

 subdivided into North and South Dakota and neither name would desig- 

 nate the locality in a sufficiently limited way. The reservation of the 

 Ponca Indians, who were a tribe of the Dakotas and from whose agent 

 •Am. Jour. Sci. (2) 36, pp. 259-261. 



