1100 Recent Literature. ee, 
ited in the region, and, while one may not agree with all their 
conclusions, the paper will always have a value in connection 
with the question of several successive glaciations and of the 
formation of the loess. Their explanation of the cause of this 
driftless area is the same that has been advanced before,— 
it is difficult to estimate. 
Professor Shaler’s study of the phenomena exhibited by the 
sea-coast swamps of the eastern United States is also a valuable. 
contribution to dynamical geology. The steps, as he traces 
them, in the formation of a salt-marsh are first, the deposit of mud 
by the currents in some sheltered spot, and next, the growth of 
eel-grass on the mud-flats thus formed. This in turn entangles 
still more mud, and soon the level is raised to where other plants 
can grow. This process is still further complicated by the forma- 
tion of sand-beaches and sand-dunes, and of these two, or even 
more, may be formed in succession, broken here and there by 
produced in abstract, so strange is the region described. Here 
strata resting directly upon those of Cambrian age, and 4 series 
of mountain-peaks and necks not easily paralleled in other parts 
of the world, other than this strange western region which the 
t twenty years have shown to be so wonderful from every 
geological point of view. 
Packard’s Fossil Arthropods.'—Dr. Packard has for some 
d in these 
the out- 
2 ba ei i . 
To the reviewer it would seem that the forms included ge 
Amphipoda, and that “ Syncarida” can at most have ould have a 
rank. A wider knowledge of existing amphipods wọ A 
x oo 
Ont ri : : i of Extinct Foss, 
he Syncarida, a hitherto undescribed nee pete vdal Schizopod : 
-Crustacea ;’”’ “On the Anthracaridz, a Family of Carboniferous Macrurous Tg? i 
Crustacea;” “On the Carboniferous Xiphosurous Fauna of 7 he Memoirs of 
y A. S. Packard Fifteenth and sixteenth memoirs of vol. ill. of the o 
the National Academy of Sciences. 1887. 
