144- 77m American Geologist. February, 1S94 
The Martha's Vineyard folds appear to be the most recent in the east- 
ern portion of the United States. Their extreme compression indicates 
a renewal of mountain-building forces in a district which has long been 
denuded and exempt from such accidents. As to whether the action 
is still going on, the author states that no movement has taken place 
since the cycle of erosion in which the topography older than the last 
ice advance was developed. There is no evidence to show that the folds 
in the Cretaceous and newer strata correspond to a series of anticlines 
and syncliues of the underlying crystallines. Professor Shaler thinks 
the conditions of folding were analogous to those in the Richmond coal 
basin, where the Mesozoic rocks have been thrown into sharply dislo- 
cated attitudes by the formation of a synclinal trough in the underlying 
crystallines. A trough of this kind may be produced by faulting. In 
the case of Martha's Vineyard there is no trace of a seaward side of 
such a trough, but it should be said that the crystallines of this shore 
decline rapidly seaward. The organic movements of southeastern 
Massachusetts occurred shortly after an extensive importation of de- 
tritus rapidly accumulated, a fact which tends to contirm the hypothesis 
that transfers of sediments in some way excite mountain-building action. 
Notwithstanding the crumpling of the strata on Martha's Vineyard, 
there was not much massive elevation. The present shore line is near 
the old one. Numerous deposits of Cambrian and Carboniferous age 
in southeastern Massachusetts contain shallow water sediments, and 
indicate, in the author's opinion, a tendency of the land in this district 
to return to the level which it has at present. 
17. Relations of mountains to continents. N. S. Shaler. The 
author notes that mountains appear to be limited to continents or to 
large islands continental in their relations. The islands of the oceans 
are volcanic peaks or peaks brought to the surface by coral-buiding 
animals. The absence of mountains rising from the sea-floor and their 
presence in continental areas leads to the assumption that there is some 
causal relation between the growth of continents and the dislocations 
of strata which occur on them. Some years ago the author examined 
the Italian peninsula and was convinced that, with the folding and 
other compressive phenomena of the mountain axes, there has been a 
progressive uplift on each side of the disturbed area. This movement 
appears to indicate that the folding and faulting have been accompanied 
by a wide-spread movement of the underlying rocks towards the seat 
of disruption, in a way to support the uplift and to elevate a broad 
belt. In many cases the highlands adjacent to mountains are due to 
sedimentation from the mountains; but, making allowance even for this, 
it is still evident, the author thinks, that the pedestal feature is a nor- 
mal element in mountain growth. This is shown in North America by 
the Cordilleras and the Appalachians. The Mississippi valley is a trough 
formed by the opposed slopes of these pedestals. The amount of the 
material which has moved in toward mountain tracts appears to be suf- 
ficient to account for much of the hight of the continents above the 
oceans. According to this view, the continents are to be regarded, so 
far as they have been dry lands, as the product of mountain-building 
forces. The primal action is the deep seated migration of matter 
toward the axes of disturbance, and a consequent elevation of the 
region where the movements occur; a secondary action arises in the 
erosion and removal of a portion of the highlands. This last is strongly 
contrasted with the first. 
For the original elevation of the continental arches, Prof. Shaler ap- 
peals to the rise of submarine folds to the surface of the sea. Those 
which fail to reach the sea-level constitute one class, and those that at- 
tain the condition of land are by the process of erosion led to a rapid 
upper development. 
18. Phenomena of beach and dune sands. N. S. Shaler. This paper 
