Chapter 09 – Santa Cruz, Patagonia and the Falkland Islands
Another 3 week delay between chapters! I’m not very good at this…
On April 13, 1834, the Beagle anchors at the mouth of the Santa Cruz, a long river running much of the way through South America. The previous voyage of the Beagle explored a short distance of this river and FitzRoy is determined to explore more of it. As such, he sends out an expedition consisting of himself, Darwin and 23 crewmen in three whale boats. They will travel inland 140 miles, reaching a point just 60 miles from the Pacific Ocean.
Often the current is too strong to row against, and in these cases a few men are left with the boats while the rest of the party continues on foot. There are signs of Indian activity in the area, and the party feels that they have been reconnoitered.
The geography of the Patagonia plains is fairly barren and plain: it’s not until the 26th, they see the first significant changes to the geological structure: they see a massive basalt “platform”, up to 320 feet high in places, even though this is well away from the nearest volcanoes. The (volcanic) basalt begins abruptly, but Darwin has been noting basaltic pebbles in the river.
What power, then, has removed along a whole line of country, a solid mass of very hard rock, which had an average thickness of nearly three hundred feet, and a breadth varying from rather less than two miles to four miles? The river, though it has so little power in transporting even inconsiderable fragments, yet in the lapse of ages might produce by its gradual erosion an effect of which it is difficult to judge the amount.
But it may yet be asked, how has the solid basalt been moved? Geologists formerly wold have brought into play, the violent action of some overwhelming debacle, but in this case such a supposition would have been quite inadmissable; because the same step-like plains with existing sea-shells lying on their surface, which front the long line of the Patagonian coast, sweep up on each side of the valley of Santa Cruz. No possible action of any flood could thus have modelled the land, either within the valley or along the open coast; and by the formation of such step-like plains or terraces the valley itself had been hollowed out. Although we know that there are tides, which run within the Narrows of the Strait of Magellan at the rate of eight knots an hour, yet we must confess that it makes the head almost giddy to reflect on the number of years, century after century, which the tides, unaided by a heavy surf, must have required to have corroded so vast an area and thickness of solid basaltic lava.
Darwin shoots a Condor (fortunately, probably an Andean Condor rather than the critically endangered California Condor). They have a habit of attacking young goats and lambs, and the local farmers have many ways of dealing with them. They train their sheep dogs to watch for them and to run out and bark to scare them off, use carcasses to lure them into taps and even climb their roosting trees at night to noose them in their sleep – apparently they’re very heavy sleepers.
The Beagles anchors off East Falkland Island. Despite French, Spanish and English attempts to control the Falklands, they remained uninhabited until the Argentine government put a penal colony there. The administrations, both British and Argentine, have had serious difficulties. The terrain is desolate and the climate terrible. Much of the islands consist of plain, undulating moorlands.
There are cows and horses living on the island, some being farmed and some having been left wild. The cows have increased in size since being left to their own devices, but the horses have shrunk and become much weaker.
Rabbits have been introduced, and are flourishing, but their range has been limited by the central chain of hills. It has long been considered that a black variety of rabbit found on the islands is a distinct species, Lepus magellanicus. However, the black rabbits are never found separate from grey-furred rabbits and can interbreed, producing piebald offspring.
This circumstance shows how cautious naturalists should be in making species; for even Cuvier, on looking at the skull of one of these rabbits, thought it was probably distinct!
Nonetheless, a footnote adds that the same set of differing characteristics (fur colour, hape shape, length of ears) are used to distinguish between the English and Irish hares, they are just a little more distinct between those two species.
A large wolf-like fox also inhabits the islands, and it is both tame and curious, though this behaviour has been somewhat misinterpreted by human visitors.
As far as I am aware, there is no other instance in any part of the world, of so small a mass of broken land, distant from a continent, possessing so large an aboriginal quadruped peculiar to itself.
Current theories suggest the warrah was either introduced to the islands by natives or else crossed during an ice age.
Their numbers have rapidly decreased; they are already banished from that half of the island which lies to the eastward of the neck of land between St. Salvador Bay and Berkeley Sound. Within a very few years after these islands shall have become regularly settled, in all probability this fox will be classed with the dodo, as an animal which has perished from the face of the earth.
They did, indeed, become extinct in 1876, just 184 years after first being discovered by Europeans.
Some of the lower-lying land contains Silurian-age fossils, with similar (but not identical) fossils to Silurian fossil beds in Europe.
There are a number of ducks and geese in the islands, including the Falkland Flightless Steamer Duck. These are flightless, but can move rapidly across the water by flapping as well as paddling. The name steamer ducks is based on this mode of locomotion. Darwin thinks that this species may actually flap its wings independently whilst doing this.
One coralline species has a bristle on each cell, and individual organisms can use these for locomotion. However, sometimes they can team up and all move in the same direction, or even turn.
In these actions we apparently behold as perfect a transmission of will in the zoophyte, though composed of thousands of distinct polypi, as in any single animal.
Darwin is fascinated by cases of cooperation amongst these sorts of colonies.
Next time: Tierra Del Fuego
May 17, 2009 at 12:41 am