390 
in which some dozen forms of great variety are shown, repre- 
sented to-day by our one species, L. 'Tudipifera. 
The one serious criticism which might be made is one which 
could be applied to nearly every recent work on palaeobotany, 
viz.: the unnecessary multiplication of species and varieties Leaf 
forms which vary between themselves far less than do the leaves 
on many an individual tree or bush are given varietal or specific 
rank. Even some genera are founded upon such slight differ- 
ences that they are open to suspicion. In this connection atten- 
tion might be called to Plates iv. and v., where Betulites Westit 
and B. Suowit with their varieties are figured. If such species 
and varieties are to be considered in the same sense as they are 
considered in botany, that is as representing each a distinct type of 
tree or shrub, then there should certainly be an earnest protest 
entered against the abuse of this too prevalent custom. Minor 
flaws might be picked out, such as the method of numbering on 
the plates, by which the figures and their corresponding num- | 
bers are sometimes so arranged that in case of hasty reference 
confusion might ensue. The scientific value of the work, how- 
ever, is what concerns the student and by him it will be heartily 
welcomed, especially so as a large number of the types described 
are identical with those from the cretaceous of Eastern North 
America and are familiar objects in the clays of New Jersey and 
southward. AL 
Trees of the Northern United States, their Study, Description and 
Determination, for the Use of Schools and Private Students. 
Austin C. Apgar. (Small 8vo., pp. 224; illustrated). 
Professor Apgar has written a very useful little book, that 
will doubtless do much toward spreading an interest in trees and 
their study. He gives good and concise botanical descriptions 
of all the species, both native and introduced, that have come 
under his notice as growing north of Virginia and Missouri and 
east of the Rocky Mountains, accompanied by illustrations of 
their foliage and in some instances of flowers and fruit; these 
illustrations have been very well drawn, and for the most part 
well selected. We note an apparent mistake on page 100, where 
the leaves of Prunus Virginiana and P. serotina have evidently 
been transposed in the make-up of the book, the obovate leaf 
