July, 1906.] 



KNOWLEDGE & SCIENTIFIC NEWS. 



475 



" It is to man useless. Nay, it is worse than useless. 

 It is at times a special death-dealer. Small, hard 

 bodies, as the seeds of fruits, entering the appendix, 

 cause inflammation and death. In the animals lower 

 than man, this organ is of great size and functional 

 importance. That of the orang-utan is long and con- 

 voluted." 



On the other hand, an eminent surgeon has recently 

 expressed the opinion that the appendix may still have 

 a certain amount of digestive function. To controvert 

 such an opinion would obviously be presumption on my 

 part; but whether or no it still retains any active func- 

 tion, the structure in question is evidently a pronounced 

 example of a rudimentary organ, and one which, by the 

 way, leads to the conclusion that man is descended from 

 an animal furnished with a long and complex cacum. 

 Incidentally, it may be mentioned that, in addition to 

 man, the only animal possessing a vermiform appendix 

 is the Australian wombat, a member of the marsupial 

 order. Truly a remarkable instance of parallelism in 

 retrograde development ! 



With Figure 4, I come to the last section of my 

 subject, and I must confess that I am by no means cer- 

 tain that it properly belongs to my subject at all. 

 The object represented on the left side of the photo- 

 graph in question is the tip of the tail of a lion, show- 

 ing the presence of a small horny prickle or spur (s) 

 buried among the terminal tuft of hair. In the natural 

 condition, it should be mentioned, the spur was com- 

 pletely concealed by the long hair, and it was only by 

 cutting away a portion of the latter that it was made 

 visible. What may be the history or use (if it has a 

 use) of this spur, no one seems to know, and I have 

 no intention of hazarding a guess. The old story, that 

 it was for the purpose of enabling the lion to goad itself 

 into a fury when about to attack, is obviously an ab- 

 surdity, more especially as it seems that the spur is 



Fig. 4-Tip o( Tail of Lion (on (he left), and ..i N.i,l i.iiled W allaliy 

 (on tllc riRht', sliowing Horny Spur and .Nail. 



develop<'d in onlv a comparatively sm.all percentage 

 ol lions. If any of my readers can sohe this problem, 

 they will be the means of removing one blank from 

 future zoological text-books. I fear it will not help 

 them much to learn that one species of kangaroo, or 

 rather wallaby, pos.sesses a very similar caudal appen- 

 dage, which is, however, of a somewhat more nail-like 

 foim, as shown at A^ on the right side of Figure 4. 



It may be added that all the figures in this article 

 have been reproduced from photographs of specimens 

 exhibited in the Natural History Rranch of the British 

 Museum at .South Kensington. 



The Petrified Forest 

 of Arizona. 



The petrified forest of Arizona is seldom visited be- 

 cause of its inaccessibility to the ordinary traveller, 

 though it is but 2,500 miles from New York. It lies in 

 a district possessing archaeologic attractions as well as 

 geologic problems, for the village of Adamana, in 

 Apache country, which is the only human habitation 

 within easy reach of the forest, is the centre of a neigh- 

 bourhood full of Indian ruins. The most interesting of 

 these ruins are those of the cliff dwellers who made 

 their homes in the minor bluffs which border the 

 canyons and plateau-like spaces of the petrified forest. 

 The extreme height of these cliffs does not exceed a 

 hundred and fifty feet, but they are identified with the 

 forgotten Indian tribes of the Hopi and Zuni; and an 

 ancient fort together with various rock inscriptions and 

 other relics and ruins give colour to the legend that the 

 Agtees once inhabited this region. The only dwellers 

 now in this great intersected plateau 5,000 feet above 

 sea-level are the historic Navajo Indians. Such are 

 the situations and the surroundings of the petrified 

 forest of Arizona, which is divided into three sections 

 marked by the same general characteristics. Frag- 

 ments of lava, beds of basalt, and the peculiar pitch of 

 the upheaved strata point to a period of volcanic 

 activity. The first casual opinion that is formed in 

 surveying the petrified tree trunks is that an ancient 

 forest flourished on the spot; that it may have become 

 submerged and petrified under the saline action of 

 some encroaching inland sea, and that centuries after 

 the great winds and sandstorms of the high plateau 

 swept off the covering of sand and silt from the tree 

 trunks. This theory, plausible as it may at first sight 

 appear, must, however, give place to the alternative 

 theory that almost the whole of the vast and remark- 

 able deposit dropped from a neighbouring plateau, 

 where it was for long embedded, and whence it was 

 eventually washed into the valley seven hundred feet 

 below. 



Quite apart from the scientific interest of the 

 .\damana forest is its wonderful picturesqueness and 

 beautv. Each step reveals deposits of topaz, agate, 

 cornelian, amethyst, onyx, and chalcedony in such an 

 advanced stage of mineralisation as almost to give them 

 place among gems and precious stones. Chips and 

 segments of gem-like chalcedony, which once were por- 

 tions of living trees, cover the earth beneath one's feet, 

 and vari-coloured columns (hard as flint and shaded like 

 the rainbow) are huddled around, still bearing the 

 familiar outline of their original forest state. The 

 colours at the sections where the trunks have broken 

 across are always the brightest, and fully suggest the 

 radiant development that can be secured by the 

 lapidary. 



In the conglomerate stratum of the plateau are still 

 embedded thousands of tree trunks, some projecting 

 and showing round the bark an encrustation of sand- 

 stone, exactly similar to that found on the surface of 

 the trees in the petrified sections at the lower level. 

 Firs and oaks were the main constituents of the once 

 living forest, vet minute search among- the deposit, 

 whi(-h covers an area of more than eight square miles, 

 has failed to reveal any vestige of acorn or cone. This 

 circumstance, together with the fact that no branches 

 have been found, that none of the trees are upstanding, 

 and that several of the short stumps have the root end 



