MEETINGS. 89 



phi/ rites ; and this would be an augite-porphyrite. These 

 rocks frequently occur as dykes in the neighbourhood of the 

 less acid granites and of diorites. 3. It is a binary granite or 

 aplete with some epidote. 



4. E. 2,556. — " Gneiss in which 2 is intrusive, Kichmond." 

 A gneiss made up of granulitized quartz and felspar, contain- 

 ing a very large amount of epidote. 



5. E. 2,557. — " Part of the same gneiss." A gneiss in 

 which much plagioclase felspar and quartz are recognisable 

 with less epidote, but otherwise like E. 2,556. It is granu- 

 litic. 



6. E. 2,558. — " Vein diorite of the district, Richmond." 

 A fine grained but holocrystalline rock consisting of plagio- 

 clase felspar, hornblende now converted into chlorite, some 

 quartz and abundant iron ores. A diorite. 



Sent August, 1896. 



1. E. 2,677. — "Dyke cutting gneiss of south side of 

 Guernsey." This rock has the composition but not the 

 foliated structure of a hornblende schist. Small angular 

 grains of quartz are abundant in it, and a few larger grains 

 also occur, also a few felspar crystals. The main mass of the 

 rock is made up of a felt of minute hornblende crystals set 

 among quartz and felspar. No original igneous structure is 

 now visible ; and for the present it will be safer to call the 

 rock a hornblende schist, remembering that it has not the 

 platy or foliated structure of most rocks of this class. 



2. E. 2,678. — "Albecq. Fairly wide dykes cutting the 

 granite W. of the island." A porphyritic diorite. Plagio- 

 clase felspar and altered hornblende set in a ground mass of 

 smaller crystals of the same constituent with a little secondary 

 quartz. All the minerals have undergone much decomposition 

 with the formation of mica, chlorite and hydrated iron ores, 

 probably owing to the influence of percolating water. 



3. E. 2,679. — Same. Practically same rock as the last, 

 but not in quite so decomposed a state. Even here, however, 

 the minerals are decomposed, but some of their original 

 characters, such as the twinning of the felspars, are still 

 visible. I see in these two last rocks nothing to connect them 

 with 2,677. Indeed, everything points to a marked dis- 

 tinction. All original igneous structure has disappeared from 

 2,677 owing to the metamorphism of the area, while the 

 two others have suffered from nothing more than surface 

 decomposition, their igneous character being quite unmistake-- 

 able. 



