GEOLOGICAL HISTORY OF SERPENTINES. 215 
congress of Bologna ; 46-47. The distinction of eozoic and cenozoic serpentines in Italy ; their geographi- 
cal distribution. 
IV.—Geology of the Alps and Apennines.—# 48. Theories as to Alpine crystalline rocks ; 49. The work of Gastaldi ; 
50. Sections by Neri and by Gerlach, in the Western Alps; 51-52. Seetions by Gastaldi; ancient gneiss, 
pietre-verdi, newer gneiss, youngest schists ; 53. Characters of newer gneiss; 54. Section in the Biellese ; 
56-57. The pietre-verdi zone in its wider and its narrower sense; 58. The youngest crystalline schists ; 
59. Great thickness of these Alpine rocks ; 60. Von Hauer’s sections in the Eastern Alps; 61. Rocks of the 
Simplon; Primitive schists of Lory; 62-66. The lustrous schists; 67. Rocks of the St. Gothard; 68. 
Granites and so-called porphyries ; 69. Classification of Alpine crystalline rocks in four groups; 70. Their 
relations to fossiliferous strata ; 71-73. Geology of Corsica and Elba; 74. Geology of Sardina; its Cam- 
brian fauna; Ordovican [foot-note]; 75. Change of views as to the age of crystalline rocks; 76-77. The 
marbles of Carrara; 78. Studies in the Valtelline; 79. The granulitie series of Saxony; 80. Conglomerates 
in Saxony and Sweden; 81-82. The Montalban series defined; 83. Geology of Eastern Bavaria; 84. 
Bojian and Hercynian gneisses ; primitive clay-slate series ; 85-86. Gastaldi on the continuity of the Alps 
and Apennines, and the geognosy of serpentines. 
V.—The Serpentines of Italy.—% 87. Pre-paleozoic serpentines; 89. Supposed tertiary serpentines ; 90. Gastaldi on 
the sedimentary origin of serpentines; 91-93. The hydroplutonic hypothesis ; Issel and Mazzuoli; 94-95. 
Pellati’s criticisms ; 96-97. The ophiolite of Monteferrato described; 98. Inversion of adjacent strata; 
99. Constitution of the mass ; 100-101. Capacci’s view of its origin: recomposed serpentines ; 102. Diffi- 
culties of this view ; 103. Proposed explanation; 104. Relations of older and younger strata; Bonney on 
the igneous origin of the Monteferrato ophiolite ; 106. Ophiolites near Sestri Levante, and near Biella ; 
107. The Staten Island serpentine. 
VI—The Genesis of Serpentines.—% 108. [a] By metasomatosis of plutonic masses ; conversion of feldspathic rocks 
to serpentine ; 109. Of feldspathic rocks to limestone; of serpentine to limestone; King and Rowney ; 
110. [b] By metasomatosis of neptunian masses; supposed change of limestones to serpentine ; to granite, 
gneiss and petrosilex ; 111. [ce] By diagenesis of silico-magnesian sediments ; 112-113. [d] By alteration 
of plutonic olivine-rocks ; [e] the hydroplutonic hypothesis ; 114 [f] By aqueous deposition of magnesian 
silicates; 115-116. Dieulefait and Lotti on the sedimentary origin of Corsican serpentines ; 117-119. Con- 
stitution of serpentine-masses ; various magnesian silicates and their relations ; hydrous and anhydrous 
species ; examples of their simultaneous formation; 119-120. Alteration of olivine to serpentine ; 121-122 
Geognostical relations of olivine; its presence in limestones ; 123-125. Dunite and lherzolite; their indi- 
genous character ; olivine-bearing schists. ; 
VIL—Stratigraphieal Relations of Serpentines.—%Z 126. Contradictory opinions; Geikie and Bonney on Ayrshire 
serpentines as indigenous and as exotic; 127. analogies from coal-seams ; 128. Stapff on the serpentines 
of St. Gothard ; their seemingly intrusive character ; 129-130. Aqueous origin of these serpentines and 
their displacements; the structure explained. 

Note—In printing the above paper, in October, 1883, the author has referred to results 
made known to him since it was presented in May, 1883; namely, the recent studies of 
Lotti, ($ 72, 73) and the experiments noted in §110.—[T. 8. H.] 
