718 



AMERICAN FORESTRY 





rapidly than that of most of deciduous- 

 leaved trees. But the conditions were 

 so favorable for preserving any wood 

 that it is perhaps strange that not more 

 trunks of deciduous-leaved trees have 

 been found there. As it is, however, 

 greater number are 



the Tertiary Period. As compared with 

 the eons of geologic time that preceded 

 it the Miocene is relatively very recent, 

 though, if the various estimates of the 

 age of the earth that have been made by 

 geologists are anywhere near correct it 



a 



known from the park 

 than from any other 

 region. Thus, the Ari- 

 zona fossil forests em- 

 braced only two spec- 

 ies of deciduous-leaved 

 trees ; the Calistoga 

 (California) wood only 

 one species, and the 

 forest at Cairo, Egypt, 

 only four species. 



The 10 species of trees 

 represented in the fossil 

 forests of the park are 

 by no means the only 

 fossil plants that have 

 been found. The fine- 

 grained ashes and vol- 

 canic mud in which the 

 forests were entombed 

 contain also great num- 

 bers of impressions of 

 plants, many of them 

 very perfectly pre- 

 served. 



The question is often 

 asked, how old are the 

 fossil forests? It is, of course, im- 

 possible to fix their age exactly in years, 

 though it is easy enough to place 

 them in the geologic time scale. The 

 forests of the Yellowstone National 

 Park are found in the Miocene series of 



Pholo by F. J . Haynes. 



FOSSIL TRUNK NEAR TOWER FALLS. 



may well have been a million years ago. 

 It must be remembered, however, that 

 this estimate involves more or less 

 speculation based on a number of fac- 

 tors which may or may not have been 

 correctly interpreted. 



TREE FILLING 



CHRISTOPHER CLARKE, of 

 Northampton, Massachusetts, 

 writing to AMERICAN FORES- 

 TRY, says : 



"I notice that in various illustrations 

 of trees that have had cement fillings to 

 preserve their life many of the fillings 

 have been left unpainted. As I have 

 been interested in this special branch of 



forestry work for over forty years and 

 have made fillings of over twenty bar- 

 rels of mixed cement in one filling, I 

 have never left a filling unpainted, us- 

 ing paint as near the color of the bark 

 of the trees as possible. Bark green 

 or nearly black are the colors usually 

 adopted and the filling is hardly noticed 

 when thus painted. 



