522 PRO€EEDI^''GS (IF THE NATIONAL MUSEUM vol.89 



or less regularly outlined object with the indivithial lobate areas 

 radiating from a center unfortunately somewhat crushed. It is also 

 true that there is considerable resemblance to the abundant supposed 

 jellyfish from the Middle Cambrian of the Coosa Valley of Alabama, 

 named BrooJx'sella alternata b}^ AValcott. This BrookseJJa occurs in 

 limestone from which the uncrushed fossil forms have been freed by 

 silicitication and weathering. Polished sections of it show a series 

 of canals, radiating from the center, but, as noted before, doubt has 

 been throwui upon the identification of this fossil as a jellyfish. It 

 may be an algal form, in which case the Grand Canyon s])ecimen 

 possibl}' had a similar origin and therefore would not have the same 

 geological significance as if it had been a jellyfish. At any rate, it 

 seems not unreasonable to apply a name to this imi)rint. fossil or 

 inorganic. 



Genus BROOKSELLA Walcott 



BROOKSELLA CANYONENSIS, new species 



Plate 64 



This new specific name is suggested for a supposed jellyfish repre- 

 sented by a single individual about 7 centimeters in its major 

 diameter, impressed and compressed upon a slab of fine-grained sand- 

 stone and resting u})on the edges of the laminations of several suc- 

 cessive ripple marks. From the central portion of the disk, which is 

 considerably crushed, the specimen continues into 8 to 10 somewhat 

 uniformly arranged lobes of fairly equal size, all stained red with 

 iron and more or less distinctly marked out by the lighter-colored 

 sandstone. The lobes all show crushing along the midline: and the 

 edge of the disk suggests a somewhat pentagonal form slightly ele- 

 vated above the surrounding sandstone upon which it is impressed. 



The above description may contain some wishful thinking, but the 

 writer believes, although the specimen does have considerable super- 

 ficial resemblance to Bfooksella. that the best proof for it as an 

 organism lies in the fact that this lobed sti-ucture is impressed uj^on 

 a series of ripple marks which elsewhere on the slab appear as dark 

 colored, rather evenly arranged layers. In other words, other parts 

 of the slab with exactly the same arrangement of sand layers should 

 show similar markings if the specimen Avere inorganic. 



Occi/r/mre. — Proterozoic (Algonkian) sandstones of the Nanko- 

 weap middle group above the lavas marking the to]) of the I'nkar 

 loAver division of the Grand Canyon series, near the bottom of the 

 Grand Canyon of the Colorado River. Ariz. 



lIoloff/pr.—V.^.y.M. No. 99438. 



U.SjGOVERNMCNT PRINriN3 CrFICE::194I 



