[Annals N. Y. Academy of Sciences. Vol. XX, No. 2, Part II, pp. 93-187, 



Pll. X-XIII. 4 August, 1910] 



THE WATCHUXG BASALT AND THE PAEAGENESIS OF ITS 

 ZEOLITES AN^D OTHER SECOJ^DAEY MIN^EEALS 



BY CLARENCE N. FENNER 



LIBRAR 



NEW YORfe 



(Read ly title before the Academy, 2 May, 1910) .ctOTANlCAL 



CONTENTS 



Page 



Introduction 94 



I. Geology of the region 95 



Conditions of Triassic deposition 95 



Igneous activity 98 



Local peculiarities of the First Watchung sheet 99 



Source of the waters which effected recrystallization and of the 



new minerals deposited 104 



Chemistry of the process by which alteration was effected 108 



Evidences as to time involved Ill 



Degree of superheating of the solutions Ill 



II. Petrography of the secondary minerals 113 



Methods of study of mutual relations of minerals 113 



List of minerals 114 



Application of the phase rule 115 



First period of alteration 121 



Albite 121 



Replacement of albite 12G 



Quartz 132 



Replacement of quartz 133 



Garnet 138 



The amphiboles 140 



Specularite . . ." 147 



Pyrite and chalcopyrite 148 



Datolite 150 



Prehnite 154 



Pectolite 157 



General results of the first period of alteration. . . lf>8 



Second period of alteration 



Progress of the changes 



Analcite 



Chabazite. heulandite and stilbite 



Laumontite 171 



Scolecite 172 



93 



160 

 160 

 164 

 167 



Qc: 



