THE YOUNG PROFESSOR 173 



let you have of our European animals what will be in my power 

 to procure and I hope you will mention your desiderata as freely as 

 I mention mine. I should greatly value all your bats, mice, rats, 

 moles, shrews, weasels, squirrels, etc. 



Though I am not much of a botanist, there is nevertheless one 

 branch of that science in which I take the deepest interest and for 

 which I would also ask your assistance. The study of trees has become 

 so important to palaeontologists, that no one who has paid some 

 attention to fossils can any longer make progress in this department 

 without studying the fossil trees and comparing them with the actual 

 flora. Now, I know you have paid much attention to this subject, 

 and to me it had acquired a new degree of interest since I have 

 ascertained that the arborescent flora of the European Miocene 

 Tertiary deposits has the greatest affinity with the actual flora of 

 the temperate regions of the United States; a result entirely unex- 

 pected, and quite contrary to most of the prevailing notions about 

 the temperature of the continent of Europe during the tertiary 

 epoch. I am now very desirous to make extensive collections of 

 all the trees and shrubs of the United States in order to trace as far as 

 possible this analogy. But such a collection cannot be found in any 

 herbarium, it must be made anew with that peculiar view; and if 

 you feel the least inclined to help me in this enquiry, you would 

 not only help me, but really help advancing one of the most interesting 

 geological questions. If you find it too troublesome, forgive me for 

 having asked for it. As fossil plants are mostly found in parts, it 

 would be necessary to have I st , young branches with the buds as 

 they are now before opening; cut such specimens as can be dried 

 between paper; 2 d , branches with young bark, one or two inches in 

 diameter; cut cylinders of about six inches length; 3 , similar cylinders 

 of the stems, old wood with old bark; then mark the tree to collect 

 at a later period, flowers, fruits, and leaves, and of the last, a great 

 number of all varieties of form from different branches and recent 

 shoots. It is almost late to begin, but I could not write earlier, and 

 in fact, it is rather imprudent for me to go to-day through the exer- 

 tion of writing; but perhaps in the thickest of the woods, you will 

 still find specimens of all your species in a leafless state, with the 

 buds in the winter state. 



