462 W. M. SutcMngs — Coniston Flags at Shop. 



granular and microlithic bodies, appear in the grains of regenerated 

 quartz and assist in distinguishing it from the still remaining 

 clastic fragments. 



At another stage still larger rutile crystals are seen in groups 

 and interlacing clusters, mustering strongly at some parts and 

 wholly absent from others. 



In some of the sections where " spots " are strongly developed, 

 clusters of beautiful little crystals of anatase are seen, as recorded 

 by Harker and Marr.^ 



At the time when they introduced the note on this mineral into 

 their paper it had been only seen by me in one section. I now have 

 several, from different points along the beck, in which it is plentifully 

 represented, not only as clusters in the spots, but also scattered 

 about in the mosaic. 



This appears to be a rare case, as Mr. Harker tells me that 

 anatase is only once previously recorded (by Lessen) as a contact- 

 mineral. It is a very interesting fact that titanic acid as original 

 slate-needles is reabsorbed in some manner, and then reappears, 

 in one and the same rock, either as rutile or as anatase, and that the 

 latter clusters thickly in special spots. 



Another form in which the titanic acid reappears is in combination 

 with lime and silica as sphene, granules of which are abundant in 

 some of the sections, though none is seen till after the disappearance 

 of the original rutile-needles. 



Again, at some parts of these rocks we have abundant minute 

 transparent plates of ilmenite, largely as perfect hexagonal crystals, 

 thickly grouped together in the spots in just the same manner as 

 we have the anatase. This appearance of ilmenite in contact-rocks, 

 with the corresponding disappearance of original rutile, is pointed 

 out by Eosenbusch (" Massige Gesteine "). 



Finally, where veins of white mica are formed, we may see, in 

 and along the edges of these little veins, large crystals and grains 

 of rutile, many times larger than any so far mentioned, resembling 

 in size and form those which are seen so abundantly in some schists. 



The occurrence of anatase in this manner being apparently so 

 rare, it may be of interest to mention that I have recently observed 

 another instance of it. A specimen of " ash," or fine-grained tuff, 

 which I collected this summer at Falcon Crag, Derwentwater, is 

 made up in about equal parts of volcanic lapilli and small fragments 

 of sedimentary rocks.^ Some of these fragments are of altered rocks, 



1 These crystals, when best developed, are about -eTuTo inch long? The form is 

 that of a tetragonal pyramid, either simple or showing also prism-faces in narrow 

 bands. In some of the later specimens there are large clusters consisting almost 

 wholly of perfect, or nearly perfect crystals. 



^ These fragments of sedimentary rock are of various slates and grits. Some are 

 very micaceous and chloritic, not very quartzy, full of " clay-slate needles," and not 

 altered in any way. They are like many common types of slates. Others are very 

 quartzy, more like the flags at Wasdale Beck, but even richer in quartz. The alteration 

 of part of these is shown by formation of some of the " regenerated " quartz, and in 

 some' cases brown mica is formed, though this is not much developed, a white mica 

 in good-sized flakes being more usual. It is in these altered, more quartzy, grits 

 or flags, or whatever they may be best called, that the anatase crystals are seen. 



