AMERICAN 
JOURNAL OF SCIENCE AND ARTS. 
[THIRD SERIES.] 
Art. IX.—Forest Geography and Archeology: a Lecture delivered 
before the Harvard University Natural History Society, April 
18, 1878; by Asa Gray. 
Iv is the forests of the Northern temperate zone which 
Wwe are to traverse. After taking some note of them in their 
present condition and relations, we may enquire into their ped- 
igree; and, from a consideration of what and where the com- 
ponent trees have been in days of old, derive some probable 
explanation of peculiarities which otherwise seem inexplicable 
In speaking of our forests in their present condition, I mean 
not exactly as they are to-day, but as they were before civil- 
ized man had materially interfered with them. In the dis- 
trict we inhabit such interference is so recent that we have lit- 
tle difficulty in conceiving the conditions which here prevailed, 
a few generations ago, when the “ forest primeval’”—described 
in the first lines of a familiar poem—covered essentially the 
whole country, from the Gulf of St. Lawrence and Canada to 
Florida and “Texas, from the Atlantic to beyond the Missis- 
sippi. This, our Atlantic forest, is one of the largest and 
almost the richest of the temperate forests of the world. That 
18, 16 Comprises a greater diversity of species than any other, 
except one. 
In crossing the country from the Atlantic westward, we 
Mississippi. We exchange it for prairies and open plains, 
