1896.] Petrography. 43 



Weed, C- M— The Cultivation of Specimens for Biological Study. Concord, 

 1895. From the author. 



Whitman, C. O— Bonnet's Theory of Evolution— A System of Negations ; 

 Evolution and Epigenesis : The Palingenesia and the German Doctrine of Bon- 

 net. Lectures delivered at Wood's Holl, 1894. From the author. 



alid Scientific and Keligious Basis ? Bos- 



Scneral Notes. 



PETKOGKAPHY.' 



The Origin of Adinoles. — Hutchings 2 has discovered a contact 

 rock at the Whin Sill, England, which, in the author's opinion, repre- 

 sents an intermediate stage in the production of an adinole from a 

 fragmental rock. It contains corroded clastic grains of quartz and 

 feldspar in an isotropic base containing newly crystallized grains of 

 quartz and feldspar. The isotropic material is derived from the clas- 

 tic grains by the processes of contact metamorphism, whatever they 

 may be, as grains of quartz are often seen with portions of their masses 

 replaced by the substance. The rock has begun its recrystallization 

 from the isotropic material produced by solution or fusion of the ori- 

 ginal grains, but the process was arrested before the crystallization was 

 completed. The paper concludes with some general remarks on meta- 

 morphism. The author thinks that the statement that in granite con- 

 tacts no transfer of material takes place has not yet been proven true. 

 He also thinks that more care should be taken in ascribing to dynamic 

 metamorphism certain effects that may easily be due to the contact act- 

 ion of unexposed dioritic or granitic masses. 



Notes from the Adirondacks.— The limestones, gneisses and 

 igneous instrusives of the Northwestern Adirondack region are well 

 described by Smyth. 3 The intrusions consist of granites, diorites, gab- 

 bros and diabases. The gabbro of Pitcairn varies widely in its struct- 

 ure and composition, from a coarse basic or a coarse, almost pure 

 feldspathic rock to a fine grained one with the typical gabbroitic habit. 



1 Edited by Dr. W. S. Bayley, Colby University, Waterville, Me. 



'Geological Magazine, March and April, 1895. 



3 Bull. Geol. Soc. Amer., Vol. 6, p. 263. 



