630 MOUND EXPLORATIONS. 



on as a sure indicatiou of age, the couclusiou reached is as Iikel.\' to be 

 correct as that based upon any other data we now possess. 



Dr. Hoy, whose testimony will be accepted without (juestion, states 

 in a little pamphlet, entitled "AVho built the mounds?"^ that white 

 elms planted in the streets of Racine, Wis., in IS-tT and. IS-tS, measured 

 in 1882 from (J to 8 feet in circumference, 2 feet from the ground. 

 Maples planted at the same time measured from 4 to 5 feet in circum- 

 ference; black and golden willows, 8 feet; poplars, 8i to feet. He 

 also makes the following statement: 



At the time Dr. Laphara and I surveyed the liirge group of mounds near Raciue, in 

 September, 1850, there was a pin oak sapling growing on the center of a small mcnind 

 situated near the house of William Bull. That sapling is now (1882) 5() inches in 

 diameter, although that species of tree is ordinarily not a rapid grower.' 



xVs will be seen from this statement, the time required for the growth 

 of one foot in this case was less than one-fourth that given by Dr. 

 Lapham. 



We may suppose that generation after generation of trees have 

 grown to maturity on the mounds, and crumbled to dust before those 

 now found on them began their existence. Such a supposition, however, 

 is wholly gratuitous, unless based upon some evidence. But no such 

 evidence has been found during the explorations carried on by the 

 Bureau, nor has any been adduced by any other explorers. On the 

 contrary, there are some reasons for believing the reverse of this sup- 

 position to be true. The roots of oaks and some other trees found 

 growing on mounds will often jienetrate to a great depth in search of 

 moisture. One instance was observed in southeastern Missouri, where 

 the roots of an oak ran down more than 10 feet, most of the distance 

 through a solid mass of clay so hard that it had to be cut with an ax. 



These roots, after the tree is dead, will, as a matter of course, decay ; 

 but they will often leave traces of their existence, especially where 

 they pass through clay or earth of any other color than that into which 

 they' are converted. 



It is not likely that several generations of trees would have grown 

 to maturity on the mounds without some of them being blown down 

 and leaving the little mound ami depression so often seen in forests 

 from this cause. Had this occurred, it is not probable that the indica- 

 tions would have been obliterated much sooner than the little depres- 

 sions and rings marking the ancient dwelling sites. 



These facts, alone, it is admitted, would not furnish a satisfactory 

 te.st of age, yet they have some bearing on the question and are worthy 

 of consideration. Notwithstanding the opinion of botanists, we are 

 j.istifled in the conclusion that the age of trees has been nmch over- 

 rated, especially as there is mu<'h error in counting rings by those not 

 thoroughly acquainted with the subject, the number given often being 



' Page 16. 



' See .ilso same jiaper in Trans. Wis. Acail. Sei.. Aits, aijil Letters, vul, vi (1881-83). ]ip. 84-86. 



