Felsite

“ Fig. 62.—Section of felsites on the Coniston Limestone group, west of Stockdale.
a, Felsites more or less cleaved; b, Calcareous shales with fossils, much cleaved; c, Cleaved felsite; d, Coniston Limestone; e, Stockdale Shales (with graptolites) .
These acid lavas are generally grey, cream-coloured, or pink, with a white weathered crust. Their texture when fresh is flinty or horny, or at least extremely fine-grained and compact. They are seldom markedly porphyritic. They frequently display good flow-structure, and sometimes split up readily along the planes of flow. ”

“ After some search I have been unable to detect a single vesicular fragment among the stones in the breccias and tuffs, and Messrs. Hill and Bonney were not more successful. Not a trace of anything in the least degree scoriaceous is anywhere to be found. The paste in which the blocks lie consists of such fine material as would result from the trituration of felsite and slate. It contains many broken crystals of felspar, with grains of clear quartz. ”

“ Feldspathic rocks exhibiting the felsitic texture in whole or in part are known as felsites. Many high authorities hold that true felsites are found only among the eruptive rocks; while others claim that they are in part, or wholly, of sedimentary origin. The writer accepts the former view. The felsites are in part acid lavas which have cooled too slowly to form a true glass, like obsidian, and yet too quickly to become truly crystalline, like rhyolite and trachyte. But they are also in large part simply devitrified obsidian. Glass is an unstable form of mineral matter ”

“ Many felsites contain porphyritic crystals of clear quartz in rounded blebs, more or less idiomorphic felspar, and occasionally biotite. Others are entirely fine-grained and micro- or crypto-crystalline. Occasionally they show a fluxional banding; they may also be spherulitic or vesicular. Those which carry porphyritic quartz are known as quartz-felsites; the term soda-felsites has been applied to similar fine-grained rocks rich in soda-felspar. ”

“ Along the margin of large bosses, like those of Mull and Skye, it frequently though not invariably has assumed a fine texture, with even spherulitic and flow-structures. But in the centre of large bosses it usually appears as coarse granophyre or as granite.
The felsites vary in texture from flinty or horny to dull finely-granular, and in colour from white through shades of grey, buff and lilac, to black, generally with porphyritic felspars and blebs of quartz. ”

“ Among the pebbles in the conglomerates of the Torridon Sandstone there occur, indeed, fragments of felsites which possess great interest from the perfection with which they retain some of the characteristic features of younger lavas. Mr. Teall has described their minute structure. They are dark, purplish, compact rocks, consisting of a spherulitic micropegmatitic, micropoikilitic or microcrystalline groundmass, in which are imbedded porphyritic crystals or crystal-groups of felspar, often oligoclase. These spherulitic rocks occasionally show traces of perlitic structure. ”

“ The alteration of felspar into kaolin or china clay is also a pneumatolytic process. and is often found along with tin veins or other types of mineral deposit; probably both fluorine and carbonic acid operated in this instance along with water. Equally common and important is the silicification of rocks near mineral veins which carry gold, copper, lead and other metals. Granites and felsites may be converted into hard cherty masses of silica. ”

“ Of their minerals felspar is usually the most abundant, and is principally labradorite and bytownite, though anorthite occurs in some, while oligoclase and orthoclase have been found in others. The felspar is sometimes very clear and fresh, its crystals being for the most part short and broad, with rather irregular or rounded outlines. Albite twinning is very frequent, but in these rocks it is often accompanied by pericline twinning by which the broad or narrow albite plates are cut transversely by many thin, bright and dark bars as seen in polarized light. ”

“ The felspar appears to be mainly oligoclase; but there are also some crystals which show only simple twinning, and these are doubtless orthoclase. The augite and hornblende are very sparingly present, the former in nearly colourless to [295] purplish crystals, the latter in tiny forms of a deep emerald or bluish-green colour, with very high double refraction. Magnetite is liberally scattered in small grains through the rock, seldom included in the biotite. Apatite occurs in very fine long needles among the felspars. ”

“ They do not contain quartz, as that mineral and nepheline are mutually exclusive. From ordinary syenites they are distinguished not only by the presence of nepheline but also by the occurrence of many other minerals rich in alkalis or in rare earths. Orthoclase and albite are the principal felspars; usually they are intergrown to form perthite. In some rocks the potash felspar, in others the soda felspar predominates. Soda-lime felspars such as oligoclase and andesine are rare or entirely absent. Fresh clear microcline is very characteristic of some types of nepheline-syenite. ”

“ In a dark red ground-mass it contains many small white or rose-red plagioclase felspars, black shining prisms of hornblende, and small plates of iron oxide. The red colour of the felspars and of the ground-mass is unusual in rocks of this group, and arises from the partial conversion of the plagioclase felspar into thulite and manganese-epidote. These minerals also occur in thin veins crossing the rock. ”

“ The felspar ranges from bytownite to oligoclase, being usually a variety of labradorite; orthoclase is scarce. The augite varies a good deal in character, being green, brown or violet, but aegirine (the dark green pleochroic soda-iron-augite) is seldom present. Among the accessory minerals biotite, brown hornblende, hauyne, iron oxides and apatite are the commonest; melanite and nepheline may also occur. The ground mass of these rocks is only occasionally rich in glass. The leucite-tephrites and leucite-basanites of Vesuvius and Somma are familiar examples of this class of rocks. ”

“ There he abode in fasting and in penitence many weeks, till feeling his end draw near, he took the ring from his finger and sent it by a herdsman to Felice. "Where got you this token?" cried Felice, all trembling with her wonderment and fear. "From a poor beggar-man that lives in yonder cell," the herdsman answered. "From a beggar? Nay, but from a kingly man," said Felice, "for he is my husband, Guy of Warwick!" and gave the herdsman a hundred marks. Then she hasted and came to Sir Guy in his hermit's cell, and for a long space they wept in each other's arms and neither spake a word. ”

“ These veins wherever I saw them seemed to consist of granite, of which the felspar was commonly of a brick red colour. The sienite itself is in general white, consisting of variable mixtures of quartz, felspar, and hornblende, and varying therefore in colour. Most commonly the felspar is predominant.
In the rocks of Mont Mado the felspar is particularly abundant, and is of a flesh colour, constituting a very beautiful variety, which is also susceptible of a fine polish. ”

“ It can't be Felicia, you think. But it is Felicia, who comes into the room, beautifully dressed. Why, she must have got up and dressed, tears and all, the instant you left the room! She comes in gallantly, carrying the powder on her nose with effrontery, denying her eyes, which still show the ravages of tears, by the gay smile on her lips; and as dinner progresses, excellent, and with Felicia all as natural and gay as possible, you wonder more than ever what the devil it was all about anyway. ”

“ Felice, though very much grieved, understanding his determination, opposed not his will. So with exchange of rings, and melting kisses, he departed, like a stranger from his own habitation, taking with him neither money nor scrip; while but a small quantity of herbs and roots, such only as the wild fields could afford, formed his chief diet; and he vowed never to fight more, but in a just cause.
Guy, after travelling many tedious miles, met an aged person oppressed with grief, for the loss of fifteen sons, whom Armarant, a mighty Giant, had taken from him, and held in strong captivity. ”

“ The hornblende- and biotite-andesites, like the dacites, have in most cases a pale colour (pink, yellow or grey) , being comparatively rich in felspar. They resemble the trachytes both in appearance and in structure, but their felspar is mostly plagioclase, not sanidine. The biotite and hornblende have much the same characters in both of these groups of rocks, and are often surrounded by black borders produced by corrosion and partial resorption by the magma. A pale green augite is common in these andesites, but bronzite or hypersthene is comparatively rare. ”

“ The other said nothing, but carefully lowered a round, compact bundle from his shoulder to the ground, and sat upon it.
At this juncture Felisi, who had watched their advent from the doorway of her father's house, saw fit to make her presence known; and a very engaging presence it was, consisting of five feet two inches and fifteen years of bronze femininity, lithe and upstanding like a boy, clad in her best sulu, a red hibiscus blossom, and a dazzling smile. But what would you? It is not for nothing that one is the eldest daughter of the chief of a village like Luana. ”

“ The rock looks like a diorite in the hand specimen; it weathers to rusty looking blocks of remarkable hardness. Under the microscope the mineral which looks greyish-black in the hand specimen is found to be olivine, colourless where unaltered in thin section; but the usual alteration to serpentine has gone on along irregular cracks, and the separated granules or iron oxide give the black colour to the mass. The felspar, which forms considerably more than half the rock, is a very fresh, though occasionally much cracked, labradorite. ”

“ If the felspar is in crystals, it is easily recognized by its cleavage: but when in grains the blow-pipe must be used, for the edges of the grains can be rounded in the flame, whereas those of quartz are infusible. If the geologist is desirous of distinguishing the three varieties of felspar above enumerated, or hornblende from augite, it will often be necessary to use the reflecting goniometer as a test of the angle of cleavage, and shape of the crystal. ”

“ Missus Catoni flitted about the place like a white butterfly, giving a touch here and there. A what-not with ten shelves was placed in a corner, and Felisi longed to ask what it was for, until Missus Catoni told her without asking.
"He is very fond of nice boots," she told Felisi; "you will see the most wonderful boots in the world presently."
"Missi Redgravie, him big fellah?" Felisi inquired, and Missus Catoni went off into peals of laughter.
"Oh, I must tell him that!" she cried. "Felisi, you're a gem! Yes, Missi Redgravie is a big fellah in his own way." ”

“ They were often seen on their lawn, dressed in loose blouses, and they had a parrot and a negro servant. Madame Aubain received a call, which she returned promptly. As soon as she caught sight of them, Felicite would run and notify her mistress. But only one thing was capable of arousing her: a letter from her son.
He could not follow any profession as he was absorbed in drinking. His mother paid his debts and he made fresh ones; and the sighs that she heaved while she knitted at the window reached the ears of Felicite who was spinning in the kitchen. ”

“ The quality of the soil they yield is not however entirely dependent on the nature of the particular felspar which yields it, but is also intimately connected with the extent to which the decomposition has advanced. It is observed that different felspars undergo decomposition with different degrees of rapidity but after a certain time they all begin to lose their peculiar lustre, acquire a dull and earthy appearance, and at length fall into a more or less white and soft powder. ”

“ But old Félice, hearing the din away off yonder,—the unwonted noise of cavalry and infantry advancing with murderous intent,—she did not understand it all, she did not even suspect the truth. You cannot wonder, for what should a soulless beast know of the noble, the human privilege of human slaughter? Old Félice heard that strange din, and instinct led her to coax her little colt from the pleasant paddock into that snug and secure retreat, the thatched stable, and there, in the early morning, they found her, Petit-Poulain pulling eagerly at her generous dugs. ”

“ Then the hot color came into her face, for Felice was very proud, and did not like to be thought inferior to her husband. When they were alone together she related what she had heard. The Golden Archer looked puzzled, for he thought that she loved him too well to care for such trifles. "We are one because we are dear to each other," he cried, and took her in his arms and cherished her.
Next day came the Mistress of the Inn to set the room in order, and as she bustled about she said, "From what kingdom comes your husband, the Prince?"
"My husband is not a prince," said Felice. ”

“ The felspars of these rocks are albite, orthoclase and anorthoclase, and they often contain soda-augite and amphiboles. Elaeolite-porphyries occur along with nepheline-syenites in such districts as the Serra de Monchique, south Norway, Kola, Montreal. Allied to them are the tinguaites (so called from the Serra de Tingua, Rio de Janeiro, Brazil) , which are pale green rocks with abundant alkali felspar nepheline, needles of green aegirine, and sometimes biotite and cancrinite. ”

“ And that was why, three days later, Felisi of Luana came to the bungalow on the banks of the Rena River.
"Something in the nature of a lady's-maid" appeared in a neat blue wrapper, and accompanied by a kerosene tin trunk lashed with sinnet. Mrs. Caton fell in love with her on the instant, and though Felisi's regard for Missus Catoni was less emotional, it was none the less sincere. She thought this white woman the most beautiful thing she had ever seen, with her coral-white skin, dark eyes, and hair of an indescribable colour. ”