LESSON XVII.

STONE FISH AND STONE LILIES.

“The floor is sand like the mountain drift,And the pearl-shells spangle the flinty snow;From coral rocks the sea-plants liftTheir boughs, where the tides and billows flow;The water is calm and still below,For the winds and waves are absent there,And the sands are bright as the stars that glowIn the motionless fields of the upper air.”

“The floor is sand like the mountain drift,

And the pearl-shells spangle the flinty snow;

From coral rocks the sea-plants lift

Their boughs, where the tides and billows flow;

The water is calm and still below,

For the winds and waves are absent there,

And the sands are bright as the stars that glow

In the motionless fields of the upper air.”

—Percival,The Coral Grove.

It was not an unusual incident that a lawn gate should have been carelessly left open, and, the gate being open, it was not surprising that a stray cow should turn in thither to feast on blue grass. Given the open gate and the intruding cow, it was in the usual order of affairs that Scroggins, our black boy, should arrive upon the scene, gesticulating and loudly remonstrant. Scroggins seized a large lump of hard clay and flung it at our neighbor’s Alderney, by way of emphasizing his objurgations. The cow was already hastening her departure, and the lumps of clay struck not theretreating cow, but the granite horse-block, and so fell to pieces. At that instant I came by, and oh, joy! as the coarse matrix of clay crumbled, there fell out of it the most perfect crinoid, or stone lily, I had ever seen. White and clean, its sharp ridges, or folds, perfect, an inch of stem in good preservation—“Scroggins! Tell me quickly, where you found the clay which you have brought to level up that hollow in the lawn?” “I done fotch him from Hopkins’ quarry, missey. A clay bank jest clost along side dat quarry, suah.”

THE STONE LILIES.

Verily then there are fossil crinoids to be found in that quarry; therefore let us take a hammer, and some one strong-armed to wield it, and away to Hopkins’ quarry. The rock of Hopkins’ quarry is of the lower Silurian. Here and there we search among the fragments torn out by blasting,and lo, plenty of portions of crinoids. The crinoid found in the clay had evidently been broken from the rock in some blast, and had been flung over into the soft clay of the bank, which had hardened about it. At last we carefully chisel from the rock a stem a foot long, and another fair, cup-shaped, fluted stone lily.

As the rock is cut away we indulge in some meditations on this beautiful form of ancient life, the animal water-lilies of the olden time. They came first in the lower Silurian, when coral was king, and in their enormous numbers they soon divided the empire of the sea with the busy polyps. Moored to the sea-bottom, waving on their long flexible stems, as fleets of pond-lilies now ride at anchor, stretching out their plume-like arms, more like flowers than animals, grew the Silurian crinoids. A few of them now remain in the deep seas, but with these few exceptions the crinoid has vanished from the living world, but has left its representative descendants in the great order to which the star-fish, sea-urchins, and sea-cucumbers belong.[36]

The adult crinoid of the Silurian was very like the larval comatula of the present age.[37]The comatula is attached to a stalk that grows upon a rock or some other fixed substance, but at the age of six months the comatula detaches itself from this stalk and swims off. In this it differs from the barnacle which, as you may remember, is free and vagrant as a larva, and attached when adult. The crinoids of the Silurian were always fastened and grew each in its individualplace, as firmly as the lilies from which they take their name.

The stem of our crinoid as it is laid bare in the rock, exhibits a series of little disks or plates. These are set one above the other to form the stem, which is often several feet long. Through all these little plates there ran a soft solid substance, like an elastic cord. As the stone which holds the fossil is laid open by our chisel, and the crinoid stem and flower-cup are well displayed, they remind us of the spinal column and brain of vertebrate animals. The great German scholar and poet, Goethe, remarked that the spinal marrow threaded through the closely united vertebræ enters the skull by an opening at its base, and expands, or blooms out, into the brain. Goethe considered this a growth like a lily; the spinal cord being the stem, and the brain the perfect flower. This white stone lily looks like a prophecy in stone of the spinal cord and its brain expansion.

When this crinoid was alive, these valves or petals, which now in the petrified specimen form a solid cup, were capable of opening or unfolding, and from them the long feathery filaments spread forth. Following our crinoid down the ages have come all the marvellous families of the radiates.

It has become a common form of speech to call nearly every animal that lives in the sea, a fish. Thus we speak of star-fish, meaning members of the radiate family which have nothing in common with true fishes, except the habit of living in water; we call mollusks shell-fish, but they are very far removed in structure from the fish-class; also we call whales, dugongs, and their kin, fish, when instead theybelong to the mammals, as we shall find when we come to study them. These star-fish, as we wrongly call them, belong to the same class as their ancient forerunners the crinoids, and the crinoids were living with the corals long before there were any fish in the ancient world. The Silurian period was almost at its close[38]before a single fish appeared in the swarming life of the ancient ocean.

The progress of life from its beginning until now has been upward, and in the main the latest forms of life are the highest forms; but this is a rule which has many exceptions. We have seen many of the lowest and earliest forms of life continue living and reproducing themselves in the present age, and also we have seen the many types of life remain which are not now in their highest development, but are degenerated examples of higher forms that existed long ago. The noblest type of life is found in vertebrate animals; but the vertebrates have many families, and it is only when we finally reach the chief class of vertebrates that we find the highest type of life. The first vertebrates that appeared were fish. In their distinguishing characteristic, the backbone composed of many vertebræ, they were a prophecy of all the wonderful orders of vertebrate animals.

The fish were of several species, and had not sprung from any preceding type of animals. In their vertebrate construction they were something entirely new in animal life. The first fish of which we have any knowledge werenot poor little weaklings, hardly capable of maintaining existence; on the contrary, they came bravely into a world swarming with great crustaceans and polyps and long-armed cuttle-fish, another fish-named creature which is not at all a fish. Among these huge and ravenous animals the new specimen held its own, and asserted its higher condition. When most of the great forms of life which had witnessed its arrival had perished with the closing of the age, the fish continued into the next era, and there thrived exceedingly, and had their turn at being world-masters. With each advancing age of the world the fish-class has gone on increasing and reaching new forms of beauty and excellence.

The crustaceans, polyps, crinoids, and nautili, which preceded the fish, had their bony structure upon the outside, and the soft parts of the body securely placed within this covering. The fish came with its bones inside its body, thus depending for safety upon its agility and its teeth. The first fishes had thick, tough skins, without scales. Their skeletons were rather of cartilage, or gristle, than of bone, but their spines were long, and their teeth were particularly large and strong. They were about the size of a dog-fish,[39]and were probably even more hideous to behold.

Among these fish, however, and perhaps the oldest of them all, were some that, while having no scales, wore great bony plates, like the side plates of a sturgeon.[40]From thecoprolites found with these fossil fish we discover that they ate sea-snails, crinoids, which were unceremoniously bitten from their swaying slender stems, and lingulæ, which they tore off the submerged rocks, as cheerfully as a boy helps himself to cherries or blackberries.

The first fragment of a fossil fish ever found, was in a bed of sandstone near Ludlow, England, and geologists have been eagerly searching ever since for more complete specimens, and to discover, if possible, traces of fish in the earlier rocks. Finally the United States Geological Survey has found earlier fish remains in Colorado. One of the most ardent students of fossil fishes was the noble man of science, Agassiz, who even as a young lad began a valuable collection of fish fossils. When we consider how many organisms must moulder away and perish entirely, for every one which survives, we need not wonder that comparatively few fossils have been found, but should rather wonder that so many have fallen into sufficiently favorable circumstances to survive.

With the next age after the upper Silurian, fish became very abundant, and in that and every age succeeding, they predominate in the waters, where the older animal forms begin to disappear. One peculiarity about the fossil fishes of the Devonian era is, that they are often found in hard, flattened, oblong concretions. When one of these lumps, like pebbles, is given a smart tap with a hammer, it splits open, and a fish or part of a fish, is found in the centre. Hugh Miller, the Scotch geologist, graphically describes in several of his works the joy with which he secured perfectspecimens of fish from such pebbles. In the Devonian age fish improved in fashion, and began to wear scales. Sometimes fossil scales are found tinged with the beautiful iris-hues which they wore in the ancient waters. Sometimes in the rocks of this and the succeeding age there are found whole beds or thick strata of fish-fragments. When these beds are opened they give forth a faint odor, like decayed fish, but all the soft parts of the fish have been destroyed long ago, and merely the bones, scales, and especially the wonderful teeth remain.

FOOTNOTES:[36]Nature Reader, No. 2, Lessons 37-40.[37]Nature Reader, No. 2, p. 127.[38]In the last months of 1890, fish remains were found in rocks at Cañon City, Colorado, belonging to the first Silurian series. New discoveries constantly change such statements as that in the text.[39]The dog-fish here meant is the dog-fish of the sea, well known on the Atlantic coast. The “dog-fish” of the rivers is a very different specimen.[40]Nature Reader, No. 3, Lesson 40ad fine.

[36]Nature Reader, No. 2, Lessons 37-40.

[37]Nature Reader, No. 2, p. 127.

[38]In the last months of 1890, fish remains were found in rocks at Cañon City, Colorado, belonging to the first Silurian series. New discoveries constantly change such statements as that in the text.

[39]The dog-fish here meant is the dog-fish of the sea, well known on the Atlantic coast. The “dog-fish” of the rivers is a very different specimen.

[40]Nature Reader, No. 3, Lesson 40ad fine.

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