Vol. XVI.] 
[Part I. 
PROCEEDINGS 
OF THE 
YORKSHIRE GEOLOGICAL SOCIETY. 
Edited bv W. LOWER CARTER, M.A., F.G.S., and 
ARTHUR R. DWERRYHOUSE, D.Sc, F.G.S. 
1906. 
ox THE ORIGIN OF THE BRITISH TRIAS. 
BY PROFESSOR T. G. BONXEY, SC.D., LL.D., F.R.S. 
In opening this discussion on the Origin of the Trias* I shall 
restrict myself, as far as possible, to what we can learn about 
the physical geography and climate of that period from the 
petrology of the system, leaving one or two points to be 
more fuUy described by others. Once for all let me express 
my obligations for many necessary facts to the Memoirs pub- 
lished by the Geological Survey, especiaUj^ that on the Triassic 
and Permian rocks of the ^lidland Counties, drawn up by 
Professor HuU in 1869, to suggestive papers on India and Persia 
by the late Dr. F. Drew and Dr. W. T. Blandford,and to one or 
two other writers, whom I shall mention in due course. 
The name Trias, I need hardly say, was given because the 
rocks of this system in the typical districts of Xorth Central 
Europe fall naturally into three groups, which in Germany 
were called, in ascending order, the Bunter, the Muschelkalk, 
and the Keuper. In our own country the second is missing, 
* At the York Meeting of the British Association, August 7th, 1906. 
