336 Proceedings of the Royal Physical Society. 
and VIII., and Part 1, Vol. IX. — From the Academy. 2. Jahrbuch 
der Kaiserlich-Koniglichen Geologischen Reichsanstalt, 1865, XV 
Band. Nro. 3, Juli, August, September. — From the I. R. Geological 
Institute of Vienna. 3. Natuurkundig Tijdschrift voor Nederlandsch 
Indie, uitgegeven door de Knoninklijke Natuurkundige vereeniging in 
Nederlandsch Indie, Deel XXVI., Zesde Serie Deel I., Aflevering 3-6 ; 
Deel XXVII., Zesde Serie Deel II. ; Batavia, H. M. Vandorp's Graven- 
hage ; Martinus Nyhoff, 1864. 
The following Communications were read: — 
I. An Inquiry into the Action of the Natural Agencies hy which Level 
Terraces are 'produced, and into the proof s thereby afforded that the 
elevation of the central parts of Scotland must have been the effect 
of a sudden upheaval. By the Rev. James Beodie, Monimail. 
In the central districts of Scotland, both on the east coast 
and on the west, littoral deposits are found, forming level 
terraces or beaches, and containing marine shells of existing 
species. Two terraces have more especially attracted atten- 
tion. The lower is from 5 to 20 feet above ordinary high- 
water mark ; the upper is from 15 to 20, or even 25 feet 
above the lower. The lower terrace varies in breadth from 
a few yards to several miles ; the upper is generally much 
more limited in its extent. The accuracy of these state- 
ments is very generally acknowledged. That these appear- 
ances indicate the action of water all are ready to allow ; 
but opinions differ widely as to the nature of that action, 
and as to the inferences to be drawn from these appearances. 
The idea generally entertained seems to be that these ter- 
races were formed beneath the water, that they have been 
raised to their present position by a slow and gradual process < 
of elevation, and that we must therefore ascribe to the 
deposits found in them a very great antiquity. In oppo- ' 
sition to these views, we are prepared to maintain that the ; 
elevation of the central part of Scotland has not been the \ 
effect of a gradual rise of the land, but of a sudden upheaval, \ 
and consequently that the calculations which rest on the | 
hypothesis of a gradual rise should be set aside. | 
I 
Formation of Level Terraces. I 
In order to understand the subject aright, we must direct 
our attention to the manner in which the agency of the 
