IV 
CONTENTS. 
NO. PAGE 
XVIII. The Glenboig Fireclay. By J. W. Gregory, D.Sc., F.R.S. 
(L. and Ed.), Professor of Geology in the University of 
Glasgow. (With One Plate), . . . . 348 
{Issued separately April 8, 1910.) 
XIX. Tuesite — A Scotch Variety of Halloysite. By J. W. Gregory, 
D.Sc., F.R.S., Professor of Geology in the University of 
Glasgow, ....... 361 
{Issued separately April 8, 1910.) 
XX. Contributions to the Chemistry of Submarine Glauconite. By 
W. A. Caspari, B.Sc., Ph.D., F.I.C. {Communicated by Sir 
John Murray, K.C.B., F.R.S.), .... 364 
{Issued separately April 8, 1910.) 
XXI. A Chemical Investigation into the Nature of the Clay Sub- 
stance in the Glenboig Fireclay. By D. P. M c Donald, 
M.A., B.Sc., Baxter Demonstrator in Geology in the 
University of Glasgow. {Communicated by Professor 
J. W. Gregory), ..... . 374 
{Issued separately 1910.) 
The Papers published in this Part of the Proceedings may be 
had separately , on application to the Publishers, at the follow- 
ing prices : — 
No. XIV., 
No. XV., 
No. XVI., 
No. XVII., 
No. XVIII., 
No. XIX., 
Price Is. 2d. 
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