662 KEPORT— 1888. 



It is not a quartzite but a granitoid gneiss or gneissoid granite, probably derived 

 from some mass of Pre-Cambrian au^e. 



' The specimen practically consists of two minerals, quartz and felspar. The 

 former occurs in grains of irregular outline, sometimes associated, and often joined, 

 as it were sewn together, by microcrystalline quartz, which also occasionally 

 extends into small patches. Numerous small enclosures give it a dusty look ; 

 many are empty cavities, some contain fluids. 



' The felspar also occurs in grains of roundish to rather irregular outline, also 

 often associated. It is much decomposed, but some is probably orthoclase, and 

 microcline can be distinctly recognised. Parts occasionally are blackened by 

 clustered granules. Without destroying the slide I cannot say whether these are 

 iron oxide or some carbonaceous material which has inliltered. As its presence 

 has no important significance I have thought it needless to ascertain its precise 

 nature, but believe it probably of secondary origin. Pather roundish grains of 

 quartz are occasionally included in the felspar, as is common in old granitoid 

 gneisses. I note a very little flaky viridite. It is possible that the gneissoid 

 structure is due to mechanical deformation of a granite, but if so reconsolidation 

 has been complete. The structure, in short, recalls a type of rock which is ex- 

 ceedingly common among gneissoid rocks which are universally admitted to be 

 much older than any part of the Cambrian, and which is, so i'ar as my experience 

 goes, exceedingly rare, if not altogether wanting in any rock of Palaeozoic or later 

 date.' 



6. The Caverns of Lvray. By the Chevalier R. E. Reynolds. 



These famous caverns are situated near the crest of a limestone hill of Silurian 

 Limestone, near Luray Court House, in the valley of the South Shenandoah,Virginia, 

 U.S.A. The valley is bounded on the east by the due Ridge Mountains, and on 

 the west by the Massanulton range, the caverns lying equidistant from each. 

 They were discovered in 1880, during which year the Smithsonian Institution sent 

 out a scientific commission for the purpose of exploring and reporting on the same. 

 The writer was a member of this commission. 



The caverns — several distinct ones united by engineering operations — are similar 

 to others found in limestone regions. They are mostly the result of erosion ; one 

 only — the Pamble, a plateau 500 feet long by 300 wide — resulting from displace- 

 ment of the adjacent strata. 



The predominating features are chambers, galleries, chasms, cascades, lakes, 

 springs, and enormous columns. 



The drapery is multiform in character, and many examples are highly ornate, a 

 few being absolutely unique. The several styles or patterns will be named in the 

 order of their growth. 



Human remains have been found, but the character of their environment proves 

 them to be of Indian origin. From the depth of the travertine which enclose them 

 they appear to have been imprisoned for nearly a thousand years. The bones that 

 are now visible consist of the right femur, the lower jaw, a rib, the segment of a 

 clavicle, and a few teeth detached from the superior max. They appear to have 

 belonged to a female of seventeen or eighteen years, the sex and age being deter- 

 mined by anatomical structure, ossification and dentition. 



Columns. — Millions of them ; some are 100 feet in circumference, and others 

 100 feet in height. 



Stalactites. — They are very numerous and both single and compound, the latter 

 forming ' sheet drapery ' a hundred feet long and equally as wide. 



Stalagmites. — Less numerous than the above, as much of the drip from the 

 stalactites is converted into travertine. 



Helictites. — Stalactites, usually small, which have ceased to enlarge vertically, 

 their drip being diverted by polar influence and capillary attraction. The result is 

 a horizontal, or obliquely perpendicular growth, in utter defiance of the 'Law of 

 Newton.' 



Travertine. — The result of a drip too excessive to permit the growth of stalag- 



