OUR 'OLOGY PAGE. ABOUT GRAVELS. BY A NATURALIST. OUNG observers, who have had a lesson in geology from books or teachers, know pretty well that the rocks beneath our feet are not mingled confusedly together chalk with sandstone, or clay with quartz, but lie for the most part in layers or beds which even school-children now have learned to call "strata." It is also tolerably well known that these strata are arranged in this country in a definite order, so that a geological map of England exhibits a series of strips running from south-west to north-east, and representing the upturned edges of a vast set of "rock formations," the newest or uppermost being shown in the south-east, and the most ancient in the north-west of the country. But, lying here and there on the top of the rocks, underneath the surface mould, are found, as most folks are aware, deposits of gravel, like those seen on so many parts of the sea-shore. These consist of fragments of flint and other sorts of rock, more or less rounded, evidently by the action of moving water, like the flowing and ebbing tides. To all these gravels the old geologists used to give the name of "Diluvium," supposing them to have been left by the receding waters of a universal deluge (diluvium). Further evidence rendered this idea quite untenable, and then the gravels and such like superficial accumulations from water action were dubbed "Drift." And drift was for many years a big puzzle that wouldn't come right. It was easy enough to understand how flint fragments could be washed out of chalk rock, and make gravel of more or less rounded pebbles. But gravels that consisted of fragments not waterworn, but sharp-angled, and composed of such rocks as could only be found hundreds of miles away, or perhaps on the other side of a great hill range-well, they were a tough problem. What could have brought them together?-so far, from so many quarters, and yet not have rolled them into " marbles ?" The answer came at last, after long and patient study of facts. Who brought them? Why, as Charles Kingsley wrote, Hrymir, the frost giant-ICE! the ice of what is now known as 66 THE GLACIAL PERIOD." In an age too far away from the present to be accurately conceived by the imagination, yet quite "recent" according to geological reckoning, our island lay submerged beneath a thousand feet and more of icy sea, glaciers occupying the northern parts of Britain and the whole of Wales; a state of things such as exists in Greenland and the Antarctic continent at the present time. Moving ice always wastes the rocks over which it travels, and carries fragments, often of vast size, in the same direction. In the Swiss glaciers the lowest extremities of these ice rivers gradually melt, and the enclosed rock fragments are left in the form of heaps of stones called moraines. The ice-sheet which overspread our country in the glacial age moved southwards, wasting the rocks over which it moved, and so bringing "specimens from hill, and mountain, and higher grounds, to where it met the sea. Here Neptune and Hrymir wrestled for the mastery, and the " old salt" proved the stronger of the two. Hrymir dropped his lapful of rocks and stones as he retreated, and Neptune became ruler of Britannia, whose destiny was one day to rule him. In plain prose, the sea, a very cold sea still, overspread the land, as proved by the shells it afterwards left on Welsh mountains, and Britain become a mere group of ice-clad islands. A SATURDAY RAMBLE. Here my narrative must stop; but I wish to tell my young readers how I spent a Saturday afternoon among the remains of the old, old glacier. It was not far from the great city; a short ride by rail brought me to Finchley, in company with a geological friend and a group of members of his Sunday class. We soon found ourselves in a brickfield adjoining the station. A heap of stones lying" promiscuous at the corner of the field speedily attracted both attention and hammers. These stones, embedded in "glacial clay," had been turned out of bed in order that the softer deposit of the ancient ice might be converted into useful material for building human habitations. We looked at them closely. It was a strange conglomeration. There were hardened boulders of chalk, shapeless fragments of sandstone, furrowed by hard grinding in the ice-mill; limestones with shells of marine origin, large nodules of London clay (the nearest and least represented formation) with crystals of quartz and remains of large oysters; lumps of greenstone and granite from mountains far away; little quartz pebbles, such as children look for on the shores of Sussex and Kent, and big quartz pebbles not yet ground down into small ones. My friend picked up a large shell peculiar to the Oxfordshire clays, and presently one of the boys found a fragment of rock in which the glacier had actually written its name in hieroglyphic scratches and grooves. We were at the southern end of what remains of the old moraine-now represented by patches of sand and gravel. Externally was a brickfield with sundry clay swamps and disreputable-looking pools, tenanted by frogs and newts, and freshwater mollusks. All around was bright with the verdure of the spring time, and it seemed hard to believe that once all this district had been lying beneath a frozen sea. Yet, with the evidence before us, it would have been hard to deny the existence of such a chapter in the past history of England. a beautiful sketch illustrating this singular and interesting group, and by the help of which, with a reference to "Withering," a beginner will be assisted to identify several species. At the top of the picture (left hand), is the Spider Orchis (Ophrys aranifera); next below it, the Butterfly Orchis (Habenaria bifolia); lower still, the Tway-blade (Listera ovata). On the right are shown the Lizard Orchis (Orchis hircina), and below it the Fly Orchis (Ophrys muscifera). At the foot of the sketch is one of those breezy uplands where, especially on a chalky soil, the orchids of our southern counties delight to dwell, "And waste their sweetness on the desert air." One of the most interesting of our native birds which stay with us all the year round is the Kingfisher, about which the ancients delighted to make pretty fables, and tell pretty fibs, such, for example, as that the bird had a floating nest on the surface of the sea, and while she was sitting there was always calm weather: hence the term "haleyon days," from halcyon, a kingfisher. The bird's real nest is far less poetical, being a hole in the bank of some river or stream, and usually smelling most unpleasantly of stale fish. The younger kingfishers partially migrate, according to Mr. Gould, going down to river mouths, or the coast, in the fall of the year, but coming inland for the summer. The bird fishes from some overhanging bough, from which it darts with arrowy swiftness on any unlucky minnow or A July day of the genuine kind is typical of an English summer, and I know of no more "summery" group of butterflies than those which are illustrated in our woodqut. The Fritillaries belong to Mr. Newman's order of Spine-bearers (Spinigeri), because their larvæ, like those of the Tortoiseshell and Peacock, are more or less covered with spines, until their last moult. The family is divided into two portions, the Silverspotted Fritillaries and the Gregarious Fritillaries, All are characterised by the upper side of the wings being beautifully spotted with black on a rich brown. Six of our native species (Argynnis) are marked with silvery spots on the under side of the wings; while the remaining three form the second division (Melitaa), being without the silver, and having catapillars which are gre. garious in their habits. Of the former, A. Paphia, Fritillaries. the Silver-Washed Fritillary, has the under side of | (M. Cinxia), the Heath (M. Athalia), and the Greasy the hind wings streaked with silver. Three other large (M. Artemis). All are under two inches in expanse. species (above two inches in expanse of wing) are the High Brown (A. Adippe), the Dark Green (4. Aglaia), and the Queen of Spain (A. Lathonia). The first has no silver spots under the fore wings; the second and third have spots near the tip; but in A. Aglaia the under side of the hind wings is greenish, whereas in Lathonia it is yellowish. The Pearl-bordered (A. Euphrosyne) and Small Pearl-bordered (4. Selene) are both smaller-under two inches in expanse. In the former, the underside of the hind wings has one large central silvery spot; in the latter, there are more than one. All the foregoing insects are pretty in form, colour, and name; they also have pretty tastes, the larvæ feeding on different kinds of violets in woods. The Gregarious Fritillaries are three; the larvæ feed on plantain and scabious, in companies, hibernating in a fasting condition, under a web of their own spinning. They are named, the Glanville The first has on under side of hind wings several rows of black spots; the second, black lines; the third, one row of black spots. Cinaia is very local in its distribution; Athalia is found only in the the South of England; but Artemis is much more common, frequenting damp meadows. WATER-FLEAS. If you have ever tried to stock an aquarium, on however modest a scale, from a neighbouring pond, you could not have failed to notice among the new inmates certain living atoms, bobbing jerkily about in the water, as if impelled by some internal gunpowder, and becoming most tantalising objects to inquiring eyes. Some of these would be Waterfleas (Daphnia), though their resemblance to the lively terrestrial creature whose name they bear is rather ghostly and remote. Naturalists include them in a division of the great Crustacean class of animals. to which they have given the title of ENTOMOS TRACA, or " shelled insects"; and this name is not so bad, for these tiny aquatics have jointed antennæ, sometimes long and branched, and facetted eyes, "for all the world" like genuine insects. A pair of shells, or a single shell folded, delicate and transparent in structure, encloses the animal's corpus, through which the various organs may be seen in action, under a powerful magnifier, the heart beating vigorously as long as the water-flea is alive and well. Our figure (Fig. 1) shows the male of the common Daphnia; the jointed feelers, the long curved stomach, the eye with its lenses, and the egg-shaped heart, are at once recognisable. FIG. 1. Another istic way in which they spin through the water, and then suddenly sink motionless to the bottom, when they can hardly be distinguished from minute mussels." There are twenty-seven British species of Cypris, not including others which are extinct, their tiny shells remaining as fossils, "To tell of that which once hath been." brother of the Sandhoppers, whose dances on their native shores can hardly fail to attract attention, for their numbers make them sometimes appear like a cloud of steam " by the sad sea wave." It is figured as No. 4, with a magnified cut of the head (b). Those of my young readers who possess, or have access to a microscope, will find a store of interest and amusement in the tribe which we have been figuring. Expensive instruments are not needed for viewing the Entomostraca. GATHERING PLANTS. A correspondent wishes to know "how to preserve (land) plants and seaweeds." As to the former, I must refer him to the hints given on page 410. To this I may now add a word or two about collecting. very common Entomostracan is the Cyclops. Our figure (Fig. 2) shows C. quadricornis, or the "four-horned" Cy. clops (female), with her curious pair of egg-bags hung behind her like John The "regular thing" is to carry a Vasculum, which Gilpin's bottles. is a japanned box, something like a flattened candleEach of these box, of extra length, and provided with metal loops to 66 sacs contains receive a strap for buckling it to the collector's side. from thirty to forty Judging from the very few times that I have seen a eggs, and when vasculum adhering to a living biped, I fear the race hatched, the larvae of outdoor botanists must be very limited, or else are so unlike their that they prefer to do the irregular thing. Neverparents, that "their theless, a vasculum or other metal box has the own mothers (one advantage of keeping your plants very fresh, till you might suppose) would hardly know them." A get home. figure of one of these young hopefuls is shown in the lower left-hand corner of his mamma's portrait. Fig. 3 gives a side and top view of another genus, Cypris with its double shell and jointed antennæ and limbs."Nothing can be more curious," FIG. 2. F. 3. says a recent writer, A friend of mine, however, whose leisure time (like my own) is always scanty, devised some years ago an ingenious substitute for the plant box. He procured a couple of stout boards, about sixteen inches long by fourteen inches wide, made sufficiently thick not to bend or warp. To these he attached a couple of cross straps with buckles; and between the Travelling Press. "than the other two, to which it looped on. boards he en closed two or three quires of white blotting paper. This formed his "travelling press," and was carried conveniently by a third strap, slung lengthwise between the Each specimen or between two of the layers of paper, the press re-strapped, and so the collector went on his way. The plants were thus in process of drying and preservation from the time they were gathered, and I can testify to their satis Vasculum. factory condition after the drying had been completed, in a larger press and under greater pressure, at home. Young collectors should remember that it is desirable to choose as perfect a specimen as they can obtain; of course, choice is not always possible, except Hobson's; and to get the whole of each,root and all, when the plant is not of too large a size (this rule does not apply to oaks or poplars). Long grasses and ferns may be bent, or a part of the stem of a plant may be cut away and the remaining portions Digger. mounted separately on the Spud. same, or, if needful, on two adjacent sheets. The two requisites in all plant collecting are neat arrangement and thorough drying of the specimens. We figure a botanical Digger," and also a "Spud," with a wooden handle, which is a cheaper article. 66 PRESERVING SEAWEEDS. The foregoing remarks apply for the most part to marine as well as terrestrial plants. Being, however, seldom seen growing in their native habitats, sea-weeds are more commonly mounted in a fragmentary condition; mere sprigs, of very little use for identifying the species, being pressed and booked. Mr. Grattann, one of our well-known authorities in Alga (alga, a sea-weed), recommends that the weeds should be gathered into an ordinary sponge bag of indiarubber, or in hot weather, a tin can, for the sake of coolness. Wash the plants well in their native pools, and repeat the process as soon as the mounting can be commenced. They may then be floated out in a pie-dish or photographer's "bath," having first laid a sheet of perforated zinc at the bottom of the dish, and over this the sheet of drawing or other unglazed paper, on which the specimen is to be permanently mounted. Raise the plant by means of the zinc, allowing the water to drain gently off, and then, placing it in an inclined position, "paint" it into position with a camel's-hair brush, and absorb the superfluous moisture with a piece of clean sponge. For pressing, a piece of blotting paper is placed underneath that holding the specimen, and a piece of calico above, then more blotting paper above and below. A change of blotting paper will be needed in a very short time, but the calico must not be removed till after the drying is completed. A towel press or screw press is best for sea-weeds; but, of course, as in land plants, this is not essential. EYES TO THE BLIND. MBOSOMED among the trees high up on the mountain slope overlooking the Lake of Lucerne, stood a charming pension. The hurried tourist, eager to reach the Rhigi Kulm, would pass it by. The invalid, the idler, the artist, longing to catch the wondrous charm of lake and sky, would surely linger here. It was late in the The lake-boats were no longer crowded, the landlord's harvest was over, and yet on one still evening in late September there were people on the balcony of both the first and second floor. Under the awning of the higher verandah sat an elderly man, a white-haired lady, and a beautiful girl. The latter gazed thoughtfully upon the hills that were purple and golden in the fading light, and listened with hushed attention to the notes of a viol that rose from the balcony beneath. "How wonderfully sweet and yet how sad the music is to-night," said the gray-haired lady, listening with half-shut eyes. "Yes, poor fellow," said the father, rising briskly, "I am going to bring him up to spend this our last evening here. He will be lonely enough when we are gone." "Do you think we shall get off to-morrow, father? "I hope so; we have loitered here too long already, though our friend below stays every autumn till the October frosts. It's a beautiful spot, but it must be desolate enough to be here alone and blind." 66 66 At the last word a slight shiver swept unnoticed over the young girl's frame, and the silence was broken next by the cheerful voice of her father on the balcony below. "Father," called the mother, softly, over the railing, ask Mr. Donald not to leave his viol behind," and he came back leading with clumsy kindliness a young man whose face wore a smile so bright that it was hard to believe that he could not see the smile that greeted him. Then, talking of the happy weeks passed together in this lovely mountain home, or singing softly, the young girl's voice mingling with the strains of the viol, the quiet sunset passed. Feeling the air grow chilly, the mother withdrew within the window, and the father dozed comfortably in his arm-chair, while a tremor, not lost to the ear of the young musician, crept into the tones of the girl as she spoke of the coming journey. To hide it she asked abruptly, "Do you know you have an unfulfilled pledge, When we first became acquainted, and Mr. Donald? you told me such interesting legends about this region, you promised to tell me how, though blind, you came to be so familiar with it." 66 tell." 66 'Yes, and I meant to do it," he answered thoughtfully, "but the story that endears the spot to me might sadden its loveliness to you, and I have no right to do that." "Oh, no," said the mother, rousing herself, we shall be so glad to know anything you will be so kind as to "Yes, tell us," said the father, half asleep. "Well, since you wish it," he said, "and since I owe to you all the joy of this summer, I think it right that You found me here, you should know something of me. where I have been coming for years, drawn to the spot as to the grave of a friend. For places I have never seen I must use my imagination; for places that I have seen my recollection serves, and in this spot I almost feel that I have sight again, for I was so familiar with it that I can seem to see the lake, the rocks and trees, the valley and the hills. I know every colour of the sky, |
