THE GEOLOGIC HISTOin' OF PLATANUS 7 



stretched across from Sicily to the site where (Jarthage was subse- 

 quently founded on the African coast, and a third united Spain 

 with Morocco. At another time the Mediterranean waters ex- 

 tended over a vast area in Southeastern Europe. The climate 

 was mild and humid and some of the finest forests that Europe 

 has ever known clothed its shores. Pliocene remains of Platanus 

 have been collected in Italy along the foothills of the rising Apen- 

 nines, from France, Spain, Styria, and Slavonia. 



The Tertiary was succeeded by the Quaternary, the fourth age 

 of the older cosmogonists who divided the rocks into primary, 

 secondary, tertiary and quaternary. The latter includes the 

 Pleistocene, and the Recent period in which we are now living. 

 The Pleistocene is marked by climatic changes which brought 

 about the extensive glaciation of the ice age, that most profound 

 factor in the distribution of modern animals and plants. The 

 most interesting Pleistocene deposits in the eyes of the botanist 

 are those of old forest beds and peat bogs. These show that the 

 plane tree was still present in Central Europe, although today it 

 is not a native in that region except as it is planted. American 

 records show that our modern sycamore was already in existence 

 with habits much like it has at the present time. Its leaves and 

 fruits have been unearthed in the clays of river terraces around 

 Morgantown, West Virgniia ; in the sediments that filled the bone 

 cave at Port Kennedy, Pennsylvania, once the lair of various 

 Pleistocene wild animals ; and in the buried river swamps of North 

 Carolina and Alabama. During an Interglacial period it spread 

 northward to Southern Canada and left its leaves in the clays of 

 the Don Valley near Toronto. 



I have written several similar brief sketches of the geologic 

 history of different American forest trees and hope to add simi- 

 lar accounts of others from time to time. My object is not 

 purely cultural. I hope that my readers will become awake to 

 the records of the ages preserved in the structure and habits of 

 our commoner forest trees. This fruiting habit acquired perhaps 

 in the Eocene three 'millions of years ago, this anatomical feature 

 of the wood acquired perhaps in the Upper Cretaceous — the 

 changing environment of the successive ages that moulded each 



