258 MESSES. E. H. EASTALL AND J. ROMANES ON [Aug. I909, 



(8) Unclassified Localities. 



Included in the general collection are a small number of 

 boulders from various scattered localities, chiefly to the east of 

 Cambridge. The most important of these are two rhomb-porphyries 

 from Haverhill and Bartlow respectively. From St. Ives come 

 two fine specimens of rhomb-porphyry collected by Prof. Hughes. 

 These are accompanied by a syenitic rock consisting essentially of 

 perthite and a great variety of ferromagnesian minerals, including 

 pale blue hornblende, augite, biotite, and probably aegirine. It is 

 probable that nepheline was originally present, though now much 

 altered ; and the rock is evidently an alkali-syenite. Another 

 specimen may be described as a quartz-porphyry of alkaline 

 affinities. 



It is evident, therefore, from these specimens that rocks of the 

 Christiania province extend over a wide range of country, from 

 Bartlow and Haverhill in the south-east to St. Ives in the north- 

 west. Our researches have not extended farther in the latter 

 direction. Mr. Lamplugh has recently discovered in a gravel-pit, on 

 the north side of the Lea Valley at Ware, a fine boulder of typical 

 laurvikite measuring about 2 feet in diameter. 



Hit chin. — The collection from Hitchin is small, comprising 

 only 26 specimens, so that it can in no sense be deemed repre- 

 sentative ; but it is of considerable importance, since it clearly 

 demonstrates the extension in this direction of ice-transport from 

 the other side of the Xorth Sea. It is well known that the glaciation 

 of the Hitchin district was extensive, and Mr. William Hill has 

 recently called attention to a deep drift-filled channel in the Chalk. 

 The Boulder-Clay is well exposed at the top of the great chalk-pit 

 in which the railway-statiou stands,, and many of our specimens 

 were obtained from here. One very large and particularly fine 

 example of a striated boulder of Carboniferous Limestone from 

 this locality has been placed in the Sedgwick Museum — as a tvpical 

 example of a boulder from a region of vanished glaciation. 



The rock-types recognized from this district include the follow- 

 ing : one rhomb-porphyry, and one plutonic rock which consists of 

 perthite and plagioclase (oligoclase) with pale uralitized augite and 

 a little quartz ; it seems to be an augite- syenite, with affinities to 

 the monzonites. There is also a specimen of Sparagmite and one 

 of the Forfarshire porphyry. Perhaps the most interesting rock 

 found here is a good example of the type identified as the quartz- 

 porphyry of Buchan Ness. We have obtained specimens of 

 Cheviot dykes and lavas, basic igneous rocks of several kinds, and 

 some metamorphic rocks, of which the most striking is a very 

 highly-altered limestone, containing some peculiar minerals. 



Bedfordshire. — There has been placed at our disposal a large 

 and very representative collection of boulders from Bedfordshire, 



