Palcontological Speculations. — Gratacap. 75 
former connection at the locality under consideration.'" 
If the Chattooga originally belonged to the Savannah sys- 
tem, and no change of position has taken place, then the next 
theory that would seem to suggest itself as explanatory of 
the evident recentness of the gorge cutting would be that the 
differential movements that are known to have taken place at 
the end of the Columbia and LaFayette in some way caused 
particular activity in stream erosion at this locality. 
Under either theory, however, the absence of a gorge of 
similar character in the adjacent Chattooga would appear to 
need explanation. 
PALEONTOLOGICAL SPECULATIONS. 
L. P. Gratacap, Am. Mus. Nat. Hist., N. Y. 
I. 
In the search for those variations whose accumulated force 
ushers in new forms in the life series, and by whose influence 
on the organism as a whole a kinetic impulse is established in 
a new direction, no more useful field of observation can be 
chosen than the detailed results of a survey like that of New 
York. In these volumes devoted to palaeontology we have 
displayed with laborious care the whole series of species, with 
their variations and blendings, contrasts and modifications, 
which the active work of the field, the combined painstaking 
labors of many students, and the criticism of a final revision 
have gathered, prepared and published. 
A very large amount of the material which formed the basis 
of these studies ,and a fair number of the type and figured 
specimens presented in the earlier volumes of the New York 
survey, and in the Reports of the Regents of the University 
are today permanently located on the shelves of the exhibition 
cases of the American Museum of Natural History. The ex- 
haustive cataloguer of these alone, now partially prepared by 
Prof. R. P. Whitfield and Dr. E. O. Hovey, sjiow their ex- 
tent, while associated with them are numerous specimens, and 
many large slab groups of species, the %vhole collection form- 
ing, certainly not a complete, but a very instructive view of 
*C. W. Hayks. and Vt. R. Campbhi.L. locality cited, p 131. 
^Bulletin, Avicrican Museum Natural History, vol. xl. 
