784 



SCIENCE 



[N. S. Vol. XL. No. 1039 



This conclusion proves the fallacy of Mr. 

 Fenneman's argument, for although the two 

 large mounds represented in the illustration 

 have never been touched by the plow, the 

 surface of the " low grassy knoll at the left " 

 has been cultivated for many years, since early 

 in the last century, and consequently its height 

 has been reduced many feet. A sketch of the 

 group made about the year 1840 and repro- 

 duced in " The Valley of the Mississippi," 

 No. 3, September, 1841, shows the mounds to 

 have been at that time of approximately the 

 same height, therefore the " grassy knoll " was 

 at one time thirty feet or more in height, and 

 it is known that during the course of its 

 destruction human remains were revealed by 

 the plough. 



Oahokia, the subject of this discussion, is 

 the largest artificial earthwork in the United 

 States. It stands in the extreme southern 

 part of Madison County, Illinois, about six 

 miles east of the Mississippi. It is in form a 

 truncated rectangular pyramid, rising to a 

 height of one hundred feet above the sur- 

 rounding plain. Its base, rectangular in form, 

 covers an area of about sixteen acres and 

 measures 1,080 feet from north to south and 

 YIO feet from east to west. Surrounding 

 Cahokia are 69 lesser mounds, some of which 

 are more than 40 feet in height. Some are 

 circular, others rectangular; the latter, includ- 

 ing Cahokia, are placed with their sides toward 

 the cardinal points. A group of smaller 

 mounds stood near the bank of the Mississippi 

 a little south of west of the main group; be- 

 tween the two were several isolated mounds 

 serving to connect the groups. On the oppo- 

 site side of the river, on the summit of the 

 ridge a short distance from the river, stood a 

 group of 26 mounds, all of which have long 

 since disappeared. These were within the 

 limits of St. Louis. 



As is generally known to those who are 

 familiar with the distribution of mounds in 

 the southern part of the country, there usu- 

 ally occurs in every group one mound which 

 is larger and more imposing than the others. 

 Often the larger work is separated from the 

 main group by an open space, again it is more 

 closely associated with the lesser mounds. 



sometimes being surrounded by them. The 

 St. Louis group belonged to the former class; 

 the larger group, with Cahokia near its center, 

 belongs to the latter. The mounds of the St. 

 Louis group, and those which formerly stood 

 on the opposite side of the Mississippi, have 

 disappeared, and many of the lesser works of 

 the main Cahokia group have been practically 

 obliterated by the plow. In view of these 

 conditions it is gratifying to know that a 

 movement is now being made to have Congress 

 purchase, and set apart as a park, an area of 

 sufficient size to include Cahokia and certain 

 of the smaller mounds which have escaped 

 destruction. This would preserve the largest 

 earthwork in America, the most imposing 

 aboriginal monument east of the Mississippi. 

 It is quite evident that Mr. A. R. Crook, of 

 Springfield, HI., is antagonistic to this move- 

 ment, but such statements as those recently 

 made by him should not be allowed to influ- 

 ence the work now being done. 



David I. Bushnell, Jr. 

 TJniveksity, Virginia 



an examination of blood-ejecting horned 



LIZARDS 



The homed lizard's (or horned " toad's ") 

 remarkable habit of ejecting blood from its 

 eye when attacked, although well authenticated, 

 is so rarely observed that it is thought by 

 many to have its origin and its creditability 

 in the little animal's dragon-like appearance. 

 Even Ditmars confesses that it took an actual 

 demonstration, witnessed only after handling 

 several hundred specimens, to upset his scep- 

 ticism. His description of the performance 

 is well knovTU.^ 



Hay (1892), Stejneger (1893), Van Den- 

 burg (1897), Brunner (1907), Bryant (1911) 

 and others have observed and mentioned this 

 peculiar habit. It is not limited to any single 

 species. 



Various explanations have been suggested; 

 among others that the phenomenon is con- 

 nected with the breeding season, that it may 

 be due to some parasite, and that it may be 

 " a secondary use acquired by a relatively few 

 forms." 



i"The Reptile Book," p. 145. 



