480 Correspondence—Captain Marshall Hail, 
R. Irvine and G. Sims Woodhead.—On the Secretion of Carbonate of 
Lime by Animals. 
W. 8S. Anderson.—The Solubility of Carbonate of Lime in Fresh 
and Sea Water. 
Dr. Traquair.—Restoration of Asterolepis maximus (Agassiz), with 
remarks on the Zoological affinities of the Pterichthyide. 
Section E. (Geography.) 
Joseph Thomson.—Report to the Committee appointed to investigate 
the Geography and Geology of the Atlas Ranges in the Empire 
of Morocco. 
W. J. Flinders Petrie—Wind Action in Egypt. 
Section F. (Economic Science and Statistics.) 
Prof. Edward Hull.—The State of our Coal Resources. 
Prof. Edward Hull.—Diagram showing the rate of Production of 
Coal during the present Century. 
Section G. (Mechanical Science. ) 
0. E. De Rance.—Records of River Volumes and Flood Levels. 
CORES Oi» 7 aNi@ ae 
——.__ 
Sir,—So many of your readers must go Alp-wards that I appeal, 
though late, to any who may visit the Chamounix district, to help me 
in a little investigation by looking out for diorites about the junction 
of the gneiss with the protogine—the inner portions of de Saussure’s 
“Artichoke.” I am prevented from doing so myself this year. 
Last summer I picked up a worn pebble in the gorge below 
Pierre a l’Hchelle, and above Pierre Pointue, both mere cockney 
points of interest on the way up Mont Blane. 
I do not remember any mass of diorite thereabouts. But it appears 
at intervals from the Mottets! to the upper Grands Mulets. I did 
not climb in search, not having sufficient time left. 
My specimen proved to be an epidiorite, under the microscope, 
with slightly banded structure. Hornblende, not orientated, pro- 
bably of augitic origin, showed two periods, one, the older, giving 
the usual pleochroic green and yellow, the other nearly colourless, 
with a cement, so to speak, of the secondary hornblende. The 
cleavage continued through this portion. There is apatite, plagio- 
clase and a ground mass which I have not properly investigated. 
I feel sure that careful study would give interesting results if 
this contact-region were investigated. Something like what my 
section gives is shown in Teall’s grand book, at plate 17. 
The problem of at least two periods of formation of the hornblende 
points to an interesting history of the Mont Blane “Artichoke” 
formation period. Marsuatt Hatt. 
Grosvenor Crus, September, 1889, 
1 The rocks exposed close to the Glacier des Bois and Mer de Glace. 
