The Study of Ndfvral Palimpsests. — Grimsley. 19 
The effect of contact uietamorphisni on the crj^stalline 
schists is less intense than on most of tlie rock types. The 
effects, consisting mainly of formation of new minerals, as 
andaliisite, silliraanite and garnets, have been described in 
the Cortlandt rocks by the late Dr. G. H". Williams. The effect 
of this form of metamorphism on carbonaceous shales is to 
form graphite, or the diamond, as in the South African region. 
The effects of contact action on clay slates have been described 
at a number of regions which serve as types; at Barr Andlau, 
in Germany, b}"^ Rosenbusch, by Lossen in the Harz, by All- 
port and Phillips in England, by Barrois in Brittany, Brog- 
ger in Norway. In these various regions it has been noted 
that the intensity of metamorphism at any given point is pro- 
portional to the nearness of the intruding rock. 
In limestone contacts the conditions are very favorable for 
tracing the beginning and development of the metamorphism. 
The limestone is observed to become more and more crystal- 
line as the intrusive rock is approached and the carbonates 
change to silicates. These changes are observed in the well 
known limestone contact region near Christiana, in Norway, 
and in the famous mineral locality of the Fassathal in the 
Tyrol. Contact action on igneous rocks has been observed at 
but few places. It has been described by Lossen in the Harz 
mountains. 
The pioneer in the study of dynamic metamorphism was 
Lossen in 1867. In 1878 Heim published his great work, the 
result of a long field study of the Alpine rocks, in which he 
developed the theory that even the most brittle rocks under 
pressure acted as viscous bodies and were deformed without 
rupture. Spring and Guembel endeavored to prove this the- 
ory by actual exjoeriment, but the rocks were crushed to a fine 
powder. 
In 1884, Lehman, as a result of microscopical study of the 
crystalline schists of the Alps, concluded that the rocks were 
crushed and recemented under great pressure, thus producing 
an effect similar to viscous bodies, a process which might 
be described as rock regelation. These two works mark a 
new phase in the study of metamorphism the world over, 
through the recognition of the fact that foliation in rocks is 
wholly independent of original structure. Parallel arrange- 
