Reports and Proceedings—Geological Society of London. 285 
heimia respectively than to the other members of the Helicopegmata 
with which they are included. 
The above notes afford but a very imperfect indication of the 
contents of this work, which is destined to exercise considerable 
influence in the advance of the science of paleontology. It is very 
generally thought that this science embraces nothing beyond dry 
descriptions of fossil species, but Prof. Neumayr shows that these are 
but the raw materials which, in skilled hands, yield conclusions of 
far-reaching interest and importance. It has been inevitable that 
the early stages of the science should have been devoted to the 
accumulation of the raw materials for future use; but in going over 
the pages of this work, we yet find numerous reminders of the 
deficiency in this respect. Much of the elementary work of the 
past has been of too superficial a character to be of service in solving 
such problems as that of descent; but there is every prospect that 
the more thorough modes of investigation, by means of thin sections 
and the microscope, which paleontologists now adopt, will in time 
clear up many of the difficulties which have confronted Prof. 
Neumayr in his present task. 
sei OusayS) JNAND) JS05/O@s is DAcn eS 
ce ae 
GuoLocicaL Soorrty or Lonpon. 
J.—April 17, 1889.—W. T. Blanford, LL.D., F.R.S., President, m 
the Chair.—The following communications were read :— 
1. «On the Production of Secondary Minerals at Shear-zones in 
the Crystalline Rocks of the Malvern Hills.” By Charles Callaway, 
Esq., M.A., D.Se., F.G.S. 
In a previous communication the author had contended that many 
of the schists of the Malvern Hills were of igneous origin. Thus, 
mica-gneiss had been formed from granite, hornblende-gneiss from 
diorite, mica-schist from felsite, and injection-schists from veined 
complexes which had been subjected to compression. As a further 
instalment towards the elucidation of the genesis of the Malvern 
schists, it was now proposed to discuss the changes which the re- 
spective minerals of the massive rocks had undergone in the process 
of schist-making. 
The schistosity was usually in zones, striking obliquely across 
the ridge, varying in breadth from a few inches to many yards, and 
separated from each other by very irregular intervals. Within the 
zones bands of maximum schistosity alternated with seams in which 
the original structure had been less completely obliterated. The 
new structure was connected with a shearing movement, by which 
the rigid mass was often sliced into countless parallel laminz or 
flakes. In a more advanced stage of alteration, the planes of move- 
ment were obliterated, and a sound clear gneiss or schist was formed. 
These foliated bands were called “ shear-zones.” 
The most important shear-zones were those in which diorite was 
interlaced with granite-veins. The following changes were noticed 
in tracing the massive rocks into the zones. The hornblende might 
suffer excessive corrosion, or it might become “‘reedy” and break 
