268 Tlie American Geologist. April. 1904. 
The program of the evening comprised two papers, abstracts of which 
follow : 
"The Occlusion of Igneous Rock within Metamorphic Schists," by 
Dr. Alexis A. Julien. The term "inclusive" is commonly applied by the 
petrographer to ordinary dikes of igneous rock, surrounded by beds of 
sedimentary rocks or of crystalline schists, intersecting them or inter- 
vening between their foliation planes. But for similar masses cut loose 
from all connections with the underlying magmatic source, swallowed up 
within strata of crystalline schists, and experiencing all stages in the 
process of reaction and final absorption, during metamorphic change, 
another term seems to be called for, "occlusion," signifying shut or 
sealed up beyond escape. Although the word is borrowed from the 
physicist, this can produce no confusion when applied to petrographic 
phenomena. Occluded igneous rocks may belong to either the acid or 
basic class, as illustrated respectively, on Manhattan island, by the earlier 
intrusions of pegmatyte, never found a? intersecting dikes, and by the 
intercalated sheets of dioryte-schist. Occlusion is usually attended by 
mechanical and chemical processes. The former consist of thinning or 
thickening of igneous masses caught between the folia of schists, during 
orogenic movements, into lenticular masses ; the crumbling and cor- 
rugation of sheets, and even rolling into cylinders ; and the forcing of the 
pasty masses along foliation planes, in the form of intercalated or "sec- 
ondary" dikes. The chemical processes usually consist of micaceous al- 
teration and ultimate absorption by disintegration and dissemination 
through the surrounding country rock. . 
In discussing this paper, professor Kemp spoke of the value of the 
interpretation to those who have studied the region. 
"Outlines of the Continents in Tertiary Times," by Dr. W. D. Mat- 
thew. The author presented a series of world-maps showing the hypo- 
thetical outlines of the continents during the Pleistocene, Pliocene. Mio- 
cene, Oligocene, later Eocene and at the opening of the Tertiary period, 
as contrasted with the modern conditions. The series was gotten up for 
use in the hall of fossil mammals in the American Museum of Natural 
History, to illustrate the geological distribution of different groups of 
mammals during the successive epochs of the Tertiary and Quaternary. 
It is intended to represent a somewhat conservative view of past changes 
in world geography, and is regarded as a working hypothesis, based on 
our present knowledge of geology, palaeontology and zoology, especial 
consideration being given to the mammalian palaeontology. 
The former extension of the Antarctic continent, so as to join Aus- 
tralia with South America, is regarded as occurring at the end of the 
Cretaceous period and is represented in the first map of the series. The 
connection with South Africa is regarded as too problematic to place 
on the map. The Eocene map shows the extreme of Tertian,' submerg- 
ence of the continents, which are represented as forming six isolated 
land masses. The three northern continents are connected throughout 
the Oligocene. Miocene, Pliocene and Pleistocene, Africa being joined to 
them by the Miocene. Soutli .American Iiy the Pliocene cpocli. The Pleis- 
