October 9, 1885.] 



SCIENCE. 



321 



to know that patches of eternal snow are here 

 found in a latitude of 37° S., about 1,500 feet lower 

 than in the European Alps in a latitude of 47° N. 

 In Australia the snow comes as far down in 37° as 

 in Eiu'ope in 52°. In New Zealand the snow and 

 ice are much more extensive than in Europe at a 

 similar latitude. This proves that the southern 

 hemisphere is colder and damper than the north- 

 ern. 



The fossil remains furnish much evidence re- 

 garding the changes of climate from time to time. 

 The fossil plants of the Phocene indicate a much 

 warmer climate, more humid and equable than the 

 periods following. The sudden banislnnent of this 

 semi-trox^ical flora shoT^^s that a great climatic 

 change must have supervened in post-Pliocene 

 times, due no doubt to the glaciation of the south- 

 em regions. A smaU pine (Pherosplioera) inter- 

 mediate between a Lycopodimn and a juniper is 

 still found in one locality adhering to the cold, 

 shady, constantly wet cliffs near the falls at Ka- 

 toomba, on the Blue Mountain. This is a Tas- 

 manian genus and is a remnant of the flora which 

 succeeded the semi-tropical phocene vegetation. 



Much more conclusive evidence of such a change 

 is furnished by the remains of extinct animals, 

 which now live only in Tasmania, where the mean 

 annual temperature is 7° lower than in the locality 

 where these remains are now found. The Pleisto- 

 cene inliabitants of New South Wales included 

 many remarkable animals. There were the huge 

 carnivorous pouched Hon (Thylacoleo) ; dipro- 

 todon, an animal holding the same place amongst 

 the Austi'alian mammals that the pachyderms do 

 amongst the fauna of other continents ; the noto- 

 therium, another large herbiverous animal ; the 

 very large horned lizard, megalania ; and the 

 flesh-eating notiosaurus. The kangaroos, wom- 

 bats and echinids attained far larger dimensions 

 than at present, and the remains of crocodiles have 

 also been found. Wherever the sofl was favorable 

 the country must have been covered with a rich 

 vegetation for the support of this army of her- 

 bivores. The precise character of the flora cannot 

 yet be determined ; but this much is certain, that 

 these gigantic animals have been extirpated by 

 some means or other. Sir Richard Owen suggests 

 that man was the cause, but of this there is no 

 conclusive proof. On the other hand, striking evi- 

 dence has been afforded by the dryness of the last 

 few seasons, of how quickly, through want of rain, 

 savannahs of waving grass may be converted into 

 desert-hke plains ; and the immediate influence of 

 these climatal changes on the fauna is fully at- 

 tested by the numbers of kangaroos and emus 

 which died last year through want of sustenance 

 on the western j)lains. 



Fragments of bones of the extinct mammalia are 

 met with in the gravels and clays at a depth of 

 over seventy feet from the surface, and their oc- 

 currence in such quantities and variety seems to 

 point to a scarcity of water which would alone 

 bring so heterogeneous an assemblage of animals 

 together. The occurrence of remains of the croco- 

 dile attests to a previous abundance of water. 

 Stinted in food supplies and unable, because of 

 their great bulk, to migrate rapidly or adapt them- 

 selves readily to the altered conditiozis of life, dip- 

 rotodon and the other large herbivores x)erished by 

 degrees from the combined effects of want of sus- 

 tenance, the raids of predatory beasts, and possibly 

 the attacks of man. The last terrible struggle for 

 existence as the supply of water fafled, must have 

 beeia beyond description. Now none of this vast 

 horde remains ; but their likeness may stiU be 

 traced in the native bear, wombat, kangaroo, etc., 

 which still survive on the mountain ranges and 

 plains as the comparatively pigmy types of their 

 gigantic predecessors. 



A CONVENIENT SYSTEM OF RIVER 

 NOMENCLATURE. 



Every tyro in geography has learned that the 

 Mattapony and Pamunkey are the two streams 

 that flow into the head of the so-called York river, 

 which is simply an estuary of Chesapeake bay ; 

 but few, I imagine, have ever been told how the 

 first of the above names is compounded, since its 

 tributaries are too small to be named on ordinary 

 school maps. 



A few weeks since, on approaching, the sources 

 of the Mattapony from the north I was a little sur- 

 prised at hearing the inhabitants place the accent 

 on the last syllable in pronouncing it. Presently, 

 coming to a brisk little mill stream and inquiring- 

 its name, I was informed that it was the Ny river. 

 Soon crossing a second of about the same size, I 

 learned that this was the Po. StiU a tliird was 

 passed not long after and this rejoiced in the 

 name of Ta. Turning to the eastward soon after 

 crossing the Ta, and proceeding some distance 

 down the course of the river system to below the 

 union of all three of these tributaries and crossing 

 back over the combined stream, this was found 

 on inquiry to be the Tapony. At last the mouth 

 of the Mat was passed, only below which the river 

 is recognized as the Mattapony. Between the 

 junction of the Ny and the Po and above the con- 

 fluence of the Ta it is said to be known as the 

 Pony, although this particular portion was not 

 traversed and this name not heard used by the in- 



