Reports and Proceedings — Geolocjical Sucicti/ of London. 237 



befoi'e, or at the commencement of, the last series of earth-movements 

 that crumpled up the strata. 



The sedimentary rocks were profusely invaded by granite and 

 diorite, and profoundly metamorphosed by contact-action. 



As reo;ards tlie agje of the rocks, the author mves his I'easons for 

 identifying the Gilgit limestones with the conformable Carbo-Triassic 

 series of the Himalaya. This series was mapped by Mr. E.. 

 Lydekker, F.R.S., in the neighbouring district of Kashmir, and it 

 has been traced up to tlie border of Gilgit. Sir Martin Conway's 

 specimens, reported on by Professor Bonney and Miss liaisin, enable 

 the author to connect it with the limestones of Gilgit. From this 

 correlation the author concludes that the oldest rock in the Gilgit 

 area is of Silurian or Lower Carboniferous age, and that the most 

 recent are of Triassic or even later age. As all the granites are 

 intrusive in the most recent beds, it follows that the granites are 

 younger than the Trias. The author gives his reasons for believing 

 that the oldest granite was erupted while the crumpling of the Gilgit 

 rocks was in progress ; but that a portion, at all events, of the 

 younger granites was erupted after the crumpling had taken place. 



The autlior offers an hypothesis to explain certain structures 

 fovmd in the Gilgit granites, including the granophyric structure so 

 common in them. 



All the Gilgit granites, the author believes, came from the same 

 igneous reservoir, the differences in them being due to gradual and 

 progressive silificatioa caused by the gradual crystallizing out of 

 the comparatively basic minerals ; the process extending over a long 

 period of time measured in years. 



2. "The Eocks of the South-Eastern Coast of Jersey." By John 

 Parkinson, Esq., F.G.S. 



In this paper the author has continued the study of the deep- 

 seated rocks of Jersey begun in a communication presented to the 

 Society last session entitled " On an Intrusion of Granite into 

 Diabase at Sorel Point (Northern Jersey)." A great resemblance 

 exists between these rocks in the north and south of the island, 

 and it is concluded that they represent parts of the same magma ; 

 but in the south-east additional complications arise, owing to the 

 intrusion of another rock before the invasion of the granite. For 

 convenience of study the district under discussion is divided into 

 two parts, an eastern and a western, separated the one from the 

 other by the western termination of the Greve d'Azette. In the 

 eastern district the granite and the intrusive rock which preceded it 

 are found ; in the western a rather different rock invades the diabase. 

 The latter is correlated with theaplite intrusion of the northern coast. 



Taking first the earlier intrusion found at Le Nez Point, it is 

 shown that it consists of a rock more acid than a diorite, but on 

 the whole more basic than the granite which followed it. Micro- 

 scopical examination indicates that it was poor in ferro-magnesian 

 minerals, and that quartz and orthoclase, though present, are not 

 found in the proportion which characterizes the granite. This 

 rock, the exact composition of which it is not easy to discover, has 



