138 Reports & Proceedings — Geological Society of London. 



(2) Into this is intruded tlie heterogeneous mass known as the 

 Central Intrusion, which consists of three main types with no 

 distinct boundaries — 



(a) At the margin occurs a fine-grained norite with pronounced mineral 

 banding. Nearer the centre of the mass is met (6) a biotite-plagioclase rock ; 

 and the centre itself is composed of (c) a garnet-monzonite. 



(3) The third large intrusion is the Carvichen Granitite, composed 

 chiefly of quartz, microcline, and biotite. 



Each of these masses produces some contact-alteration in the 

 surrounding foliated or non-foliated rocks. Where the ■ Central 

 Intrusion or the Carvichen Granitite is intruded into the eai-lier 

 norite, a norite containing cordierite is produced. The original 

 norite, by absorption of sediment, produces also along its margin 

 a cordierite-norite. Similar types have been described by Professor 

 A. Lacroix and Mr. A. N. Winchell. 



Both tj^pes of cordierite-norite tend to pass into a rock composed 

 essentially of plagioclase, biotite, and garnet; and this change, with 

 the gradual destruction of the hypersthene, can be seen in various 

 stages. 



2. " The Glacial Geology of East Lancashire." By Albert Jowett, 

 D.Sc, E.G.S. 



The area dealt with comprises the western slopes of tlie Pennines, 

 from Boulsworth Hill to Blackstone Edge, and their westerly- 

 offshoot, the Rossendale highland, which separates the basin of the 

 Kibble from that of the Irwell and Mersey. 



Three types of drift have been recognized — 



(1) Local drift, consisting of materials which can be found in situ in the 



neighbourhood, chiefly Coal-measures and Millstone Grit. 



(2) Eibblesdale drift with Carboniferous Limestone, chert, and Silurian 



grit, as well as local material. 



(3) North-western drift, which, in addition to any or all of the above- 



mentioned constituents, contains igneous rocks from the Lake 

 District and the south-west of Scotland. 



The distribution of the drift and the evidence of striated rock- 

 surfaces suggest the invasion of this area by an ice-sheet wliich 

 reached up to the Pennine watershed, and projected ice-lobes across 

 it through the gaps at Widdop, Gorple, Cliviger, and Walsden. 



A small unglaciated region occurs a few miles south-west of 

 Todmorden. 



In the north-eastern portion of the area the general direction of 

 ice-movement was from north to south ; in the west it was from 

 north-north-west to south-south-east, but on the south of the 

 Rossendale highland the direction of flow curved round towards the 

 east-north-east, and ultimately, in the neighbourhood of Kochdale, 

 towards the north. 



The local drift is believed to have been produced by the over- 

 lapping of 200 feet or so of clean ice, which formed the upper portion 

 of the ice-sheet, beyond the limits reached by the ice containing 

 erratics. No evidence of local glaciation has been found. 



The limit of the north-western drift rises at the rate of about 



