The San Francisco Call. Newspaper, June 1, 1902, Page 6

HE SUNDAY CALL. author Spencer. rd sl agara [ ds, down to the d the Carib- that the e at more than two miles ude. Herein, as ses of the volcanic g in such great dis- Gulf of Mexico Drained Into Pacific. At the time North and South America were together by of the a xico and Central the valley of what Mexico was drained 1 across Mexico by pec isthmus, and the ean Sea discharged o the Pacific Ocean. Then Islands formed the back- submerged continent. xisted long before yet from the stand- it was very recent, glacial period North rica were connected and ude of two miles or more. es of level of land and a long period, there s of animals be- riod During the ¢ sea, which occup were many migr of “Reconstruction of the An- seological and Physical Development Cuba, Jamaica, he Du- Great and “History the where inter in such, for in- found in even the outh Am in the early re rica pleisto- During this period of high elevation the deep canyons were formed upon the sur tzce, which cut up the continent now Windward Island region into flls and valleys, which, uent subsidence, left o E the isolated chain of islands which califthe Wind d group; but the s side d even these smaller area than we now find, owing to the subsequent rise in the land, which enlarged their area, but the drowning of the island land just mentioned, and which occurred in the middle of the pleistocene pericd, after the early glacial epoch, cx- terminated the animals of the islands, which have not since been repop ed, as such could not migrate thither from either continent owing to the broad in- tervening straits. Represent the Sunken Continent. In a general way, the Windward Isl- ands represent the sunken continent. Central America and Mexico illustrate the earth’s movements accompanied by vol- capic activity of the western - region which has been raised into high platea while the eastern region had been sink- ing. Thus in that regio repetition of the features discovered by the soundings about the Windward Isi- ands Th two great lines of volcanic activ- ity, situated thousands of miles apart, have no connection with each other wha:- ever, and the coincidence of stupendous activity occurring in the two localities only goes to show that terrestrial move- ments are now in progress along both margins of the continents. These move- ments are along lines of weakness. In the first place, great heat is developed by the great friction. In the second place, these weak lines facilitate the es- cape of the molten matter which may arise, either through a friction of the earth’s crust of from the cisterns of lava beneath. While the volcanic eruptions are more tricted in the area of action occupied by the rth moveme: are felt in th rm of Indeced, . the even one inch in the rocks at consider may produce a very ~damaging e over hundreds. of mifes of ex- i the voleanik aefivity "eampy vd h the earthquake shieks gives only very limited evidench~of: the great éarth movements in progress, which are very slow Returning now to ithe Windward Isl- ands prover, we find a double chain of islands extending from ‘hcar the coast South America to St. Martin up, and thence “winging. around 4o rto Rico, 1 and Cnbd, on one an the Bah s on the other un: almost join our Southern State v would do so were not the eys completely submerged. 4 S ns with Gr of South Americs st number of small islands rising above a submarine plateau inner the now less than 200 feet below the sex. A Chain of Voleanoes. Continuing in this chaipvare St. Vin- Lucia, Martiufijue, Dominica, mountainous portions of 'Guadeloupe, Nevis and the island 0f St. Kitts,* be- nd which the chain ‘becomes broken down into the numerous virgin islands ng up out of a’shallow sea. From . in the Grenadines Kit a repetition of volcanic cones to heights of 4000 or 5000 feet. stward of this chain we find Barba- some sunken banks east of Mar- tinique, Grande Terre, or the great lime- stone plains of Guadeloupe, parts of Antigua, Barbuda, St. Martin and An- a. The chain eads in Sombrero, the lighthouse to the West Indies; but again begins in tLe Bahamas, the re- mains of great coastal plains like those along our Atlantic, which escaped the Gestruction of the W region when it stood at the elevation formerly mentioned. This outward chain is no- where volcanic, but it is liable to earth- quake action, and throughout these isl- ands it damage is periodically pro- duced. Some of the earthquakes of these isl- ands arise directly from the volcanic activity of the inner chain. They come from the slipping of the earth’s crust, such as that at Charleston, far removed from volcanoes. There is no reason to suppose, however, that our Atlantic bor- der should be permanently free from earthquakes any more than the coast of Carolina. It must not be supposed that the whole of the Windward chain was born o. volcanoes such as we see in the ele- vated peaks of to-day. In fact, the foundations of all are of very great age, although they were carved out by the atmosphere and the rains from older vol- canic materials, but so ancient as not to be the ancestors of the modern cones. Indeed, the southern part of Martinigue, THE MYSTERY OF “VULCANITY.” ULCANOLOGISTS” of to-day are as much at a loss to define they volcano as were the geologists and astronomers of the days of Dar- win. . y” js as much a stupendous mystery to the Christian students and observers now hurrying to the scene of the unparalieled disaster at Martiniqu was the new coined word of heathen ori- to the La 1 survivors who gazed in upon the ruins of Pompell. Similar were the conditions; similar the ignor- ance of the epectator. Among the first and best equipped of special students to leave for St. Plerre was Dr. E. O. Hovey, curator of the de- partment of geology in the American Museum of Natural History. I found him rushing to make ready for his de- perture the next day on the Government relief ship Dixie. There was only time for him to speak in a general way of the previous investi- gations of leading geologists. He was mindful mostly of the large opportunity opening to him for personal observation, but he outlined certain salient results of the studies of such men as Professors Dana, Russell, Judd, Bonney and HIill, the last named having prepared a mono- graph on volcanic conditions in the West awe Hovey’'s suggestions of the has been Indies. From Dr. and other sources this sketch known facts about volcanoes carefully complled. The number of great habitual volcanic vents upon the globe is estimated at be- tween three hundred and three hundred and fifty. There is but one on the whole continent of Europe, Vesuvius, though elsewhere in the Mediterranean there are six—Stromboli and Vulcano, in the Li- parl Islands; Eina, in Siclly; Grahams Island, a submarine volcano off the Bicllian coast, and Santorius and Nisyros, in the Acgean Sea. The African conti- nent is known to contain ten active vol- caxoes, four on the west and six on the east coast, and there are about ten others on neighboring islands. In Asia there are twenty-four active volcanoes, but no less than twelve of these are situ- ated on the peninsula of Kamchatka. There are no volcances in Australia. The American continent contains more than the countries of the Old World— twenty in North America, twenty-five in Central America and thirty-seven In South America. Thus, taken altogether, there are about 117 volcanoes on the great continents and nearly twice as many on the islands scattered over the several oceans. These volcanoes usually assume in their distribution a linear arrangement, and nearly all of them have been thrown up along three well-marked bands and the branches proceeding from them. The whole eastern coast of both the Americas was thought to be entirely free from volcanoes of anything like recent date, and, just as Professor Judd a few vears ago complacently asserted, “az a matter of fact, the actual amount of damage to life and property which is af- fected by volcanic eruptions is small,” 80 Professor Benney declared that the whole western border of the Atlantic is destitute of volcanic activity, ‘“were it not for the long island chain of the Les- ser Antilles which separates that ocean from the Caribbean Sea.” R. T. Hill made a special study of conditions in the Windward Islands. It had been well known that many of the ‘West ‘Indian islands are of limestone, chiefly coraline; that some contain crys- talline rocks, while others are volcanic. Quite recently it was noted that seven craters still gave signs of life by emit- ting steam and that the curving line of volcanic vents occurred on a submarine plateau between the deep basin of the Central Atlantic and that of the Carib- bean Sea. The activity of the Soufriere ©: Bt. Vincent was remarked years ago. occupation. &ios YOLCANOES . FAOM YOLEMN OES'BY TR BONNEY. X COPY RIGHT BYQ. PVTNAMEIONS 03¢ i1D.sAs most' of St. Lucia. St; Vincent and foundations of Dominica belong” to axtient formation, but the volcanie.c méntioned had their birth ng longer, than about the beginning of the glgcikl* period. 2 P ~Bince 1he historic period sgfne of the isl 1ds5 T Bate: never’ béen” inis activity though the cones « pletég such j: 1- and cralers ‘are . cong- i Nevis, Many: eruptipas 1 con . tegpried it the ‘motn s of G loupé,s but’ T betleve nene s occurred there since the earlier part"githe nineteenth century. Dominica had ht eruption about: 1880, Bug'Mar- Kitts tinfqi Wwas supposed to’' be quiesbent un tii ‘theipicént indications’ s few month singg; % hieighbor, St Vincent, erupted 812 @nd ddrkened the Sun for a period ol élghty=three days at Barbado dred milés away, when thé whele of ‘that’island was covered ‘with the ashes: ] St Vincent Isle of Calamity. The island ot St. Vincent is one of the most Beautiful of the group, but at the same timé is one of the most calamitous Three or - four years a hurricane swept over'it, when every tree is said to have been broken off, buildings destroyed and _even the: insects swept from the land, and now . we find another destruc- tion scarcely inferior to, that of a century ago. In the island of Martinique we find the northern side of Mont Pelee gently de- scending in the form of sloping plains to the sea, with here and there a baby vol- On the western side of the moun- no. tain the descent is. comparatively e and we fin@a high, elevated terrace just back of the town jof St. Pierre, which lay on a narrow ledgeé between the, terrace and the This terrace, however, i bisected by the valley of the mountai torrent, which made an excellent path- way for the laya and the volcanic mud In theso which overwhelmed the volcanic eruptions the great danger not so much from the streams of lava as fiom the streams of mud formed by the condensing steam and hot ashes blown oft the top of the mountain by the explo- sions of vapor produced by the inflltration of waters into the molten laya itself. The greater West Indian isiands have scarcely any traces of volcanic eruptions except in ancient times. g Whole s cous matter accur along the eastern s of our North and South American mountains, still there are no remains of voleanic cones in Iastern America_except a few in the vicinity of Montreal, which is built upon the flanks of an ancient volcano. The changes of level upon the Pacific coast of North and South America have been much more stupendous in later times than those on the eastern side, and consequently we find many more and greater volcanoes, Many of these are fre- quently in a state of activity. Thus we find Orizaba, a cone rising to a height of about 10,000 feet above the ancient Mexi- can plateau, which itself is 8000 feet above the level of the sea. Colima, only a short distance south of Mexico City, is fre- quently in eruption. : In Guatemala, Santa Maria, which gave rise fo the terrible destruction on April 18, began to be active last November, and is' now said to be more active than any volcano known in America since Spanish | can frontier, Chingo, on the Salvador bor- | der, is aiso in a state of general actlvity. Never So Many Eruptions as Now. Again in Alaska another volcano is in eruption. So many widespread @ruptions in the northern ~continent have —never been krown in the historic period. Some twenty-fiye miles south of Guate- mala City is the old site of the city itself, one of the most magnificent spots in the world and having a most delightful cli- mate. Nestled in a beautiful valley among the mountains lies the city of Antigua. From one side rises the regular solitary volcanic cone of Agua, while a little fur- ther away, on the other side, is the vol- cano of Fuego and its companion. Fuego is said to be always hot. The crater of Agua was filled with water ‘when in the middle of the sixteenth cen- tury it burst and overwhelmed the orig- inal site by a flood and buried it in vol- canic ashes. The city was moved three miles farther away and grew to be one of great magnificence. In 1781 an earthquake Ieveled it, leaving the ruins of seventy- six churches alone, some of great mag- nificence. Then the city was moved to its present site, twenty-five miles away over the mountains. Iceland and the Hawailan Islands are examples of isolated cones rising out of the dei‘p oceanic abysses. At recurring places hlong the whole Andes there is a Buccession of great volcanoes, of general- ly greater magnitude than in the north- ern_hemisphere. ‘While there have been many earthquakes recorded, still there ave been only two eruptions vividly before us While that is near the Mexi- .. equal to that of anclent Vesuvius, and both of these within our memory—that of Martinique last week and the still greater eruption of Krakatoa, in the Straits of Sunda, southeast of Asia, in 1883. So great was the eruption of Krakatoa that it filled the atmosphere of the whole world with minute volcanic dust, which for months produced the crimson glow of sunrise and sunset, so noticeable even in this country. At that time a wave was produced in the sea which overwhelmed many cities on the neighboring coast and was recognizable around all the conti- nents. ‘While the volcanic activity of the Wind- ward Islands appears to be ing out, still all thcse mentioned as having cones are liable to reawakening activity, but less. so_than those at the extreme north ern end of the chain. The tension on the earth’s crust having been somewhat re- lieved by the eruptions at Martinique and St. Vincent, early activity would net be expected. Wherever there are chains of cones, with one occasionally active, there is al- ways danger of other cones bursting into eruption, and most dangerous of all are those peaks which have been quiescent so long that their dangerous character has been forgotten. — UNCERTAINTY OF VOLCANOES.' BY PROFESSOR HENRY SHALER WILLIAMS OF YALE. BALLY, there is absolutely no telling what the volcanoes may do,” sald Henry Shaler »Willlams. Silliman professor of geology in Yale University. *“They are not well understood by any one, for the laws upon which they operate are not well known. There are certain signs by which experts can tell within a compara- tively short time what some of them are likely to do; but in the instance of some other volcanoes they may break forth without any warning at all. “‘Speaking only from what I have read of the recent eruption in Martinique, and from what we know geologically and his- torically of the region, I am of the opin- ion that inasmuch as there was . more than one eruption, it appearing that there was also one on St. Vincent, there will be no immediate successive eruption. The tendency will be to subside, now that some relief has been afforded the vol- ic forces beneath the surface. ‘But ' eruptions sometimes come in series, Then, too, it may be that the two volcances which are still more or less active, Soufriere and Mont Pelee, work somewhat as Mount Vesuvius and Mount Etna have been known to work, the one inactive while the of ts. more or less violently. “A volcanic eruption is, on a grand scale, an explosion caused by the gener- ation of steam in the great boiler under the surface. I am of the opinion that therc were some great crevices in the vicinity of the Island of Martinique, through which water either percolated for many years or by the subsiding of the sea a great inrush of water took place. The fact that the sea is said to have sunk a number of feet there would seem to indicate that there is a very great crack or crevice somewhere, and that the water that rushed in was great in volume. That produced a generation of steam® which found vent through the craters of the two volcanoes, “Out, In our own Yellowstone | Park the geysers are instances of this steam gen- eration. The voicanoes there have not been active for thousands of years, but the earth has not cooled very far down yet, and the steaming water that spouts out and up is in the nature of its action volcanic. In Mexico not very long ago there was ome volcano, long inactive, upon which the rocks were still so hot that one could light a cigar by touching the end of it to the stone. “The modern scientific theory of the emission of lava is simply that the tre- mendous pressure upon the rocks, down a few miles, is so great that despite the in- tense heat they are kept not quite mol- ten, almost solid, perhaps. ‘“When the explosion takes place, reliev- ing the pressure, it happens oftentimes that the rocks turn from their solldified state to a molten condition. Men spoke of the red hot mud that poured down the mountain. When that matter comes to the cooler air at the surface, especially if there is water with it, it is broken up into fine particles by atmospheric influ- ences, and fa'ls for great distances in the form of what people desciibe as ashes. They are not ashes, however, but par- ticles of lava. “As to whether there will be sympa- thetic action of volcances in other parts of the world, I rather doubt that. [ think the easement is local, as was the disturb- ance, and that there will be no effect at any great distances. The thunder and lightning which accompanied, or followed, the eruption in Martinique were due to the fact that the tension of the electric forces in the air was disturbed. The disturb- ances in the center of the earth being very great and having an upward tendency in relieving, there follow great changes in the configuration of the territories. Great masses of rocks siide and the earth opens. That is an earthquake effect. It is pos- sible that those effects are felt at great distances. “Volcanoes are peculiar in their dction. We really know but very little about them. Scientists collect all the data pes- sible and study them carefully, but un- fortunately it is not possible to study them in action with safety. You know, down at the bottom of the rich Comstock lode, thegatmosphere is still so hot that it costs more to cool the air than the gold is worth when mined, and volcanoes Rave not been active in our country for & long ¥