316 Scientific Intelligence. 
In the heart of the South American Cordilleras, almost on the 
boundary between Chili and the Argentine Republic, northeast 
of Santiago, the author met four different localities where typical 
granitic and dioritic rocks occur in the midst of the prevailing 
andesitic lavas, tuffs and breccias. One of these is in the San 
Antonio, and three in the Juncal valley, which penetrate the 
mountains in a northeastward and eastward direction from San 
Felipe. These localities were seen by Darwin, who described the 
rock under the name of “ andesitic granite” in his Geological 
Observations in South America. (London, 1846.) 
Professor Stelzner concludes that from a purely petrographical 
standpoint these rocks are totally distinct from the andesites, and 
are in no way to be distinguished from the most typical Archzean 
granites and diorites. From a study of their field relations, how- 
ever, he finds that they are undoubtedly the youngest rocks of 
the, region, breaking through and sending apophyses into the 
andesite tuffs and accompanying sediments. ‘To reconcile these 
two facts, he assumes that they are late-Mesozoic or Tertiary 
eruptive masses which have slowly solidified under conditions of 
high pressure and temperature. Inasmuch as Darwin’s descrip- 
tions of these ‘‘ andesitic rocks” laid specific stress upon their 
recent formation, the author proposes to reserve this term (Anden- 
gesteine ” for oranitic rocks of .tertiary age; and speaks of “ An- 
dengranit ” (andesitic granite), “ Audensyenit ” (andesitic sye- 
nite), “* Andendiorit ” (andesitic diorite), ete. 
Many other descriptions are quoted from Darwin, Stiibel, E. 
Williams, Clarence King and Zirkel, which indicate the occurrence 
of similar rocks at many localities in the Cordilleras of both 
North and South America. 
In urging a more careful examination of these rocks in future, 
Professor Stelzner expresses the following opinion, with which 
geologists the world over are daily becoming more and more 
willing to agree. “Sie (die Andengesteine) werden uns, wie ich 
meinerseits glaube, immer mehr und mehr erkennen lassen, dass 
die gréssere oder geringere Krystallinitit eruptiver Gesteine 
keineswegs, wie man so lange und so hartnackig behauptet hat, 
von der Alter der letzteren abhiingig ist, sondern lediglich von 
den pbysikalischen Umstiinden, unter denen die mineralische 
Differenzir ung und Erkaltung der gluthfitissigen Magmen vor 
sich ging.’ GEO. H. WILLIAMS, 
6. “Report for 1885, Geological Survey of Canada; A. R. C. 
Sretwyn, Director.—This volume contains reports of much valua-. 
ble geological work. A few facts are here cited. Mr. Selwyn 
states, in his review of the work of 1885, that Mr. Ells has been 
investigating Quebec, north of Vermont, New Hampshire and 
Maine; and besides mapping the Silurian area, which in part in- 
cludes metamorphic rocks, has found, from the intimate connection 
between the altered Silurian slates and associated granites, that 
the granites are, ‘“‘as in New Brunswick, probably Devonian.” 
In the report on New Brunswick, by Mr. C CHALMERS, it is stated 
— 
