620 NATURAL HISTORY OF QUITO. 
` nately on either side of the Andes, from an ignorance of the 
geography of the country. Our generalizations lose half their 
value from this want of care and precision. ‘‘ Could we only know 
the range of a single animal as accurately as Alphonse De Can- 
dolle has lately determined that of many species of plants, we 
might begin a new era in Zoology. It is greatly to be regretted 
that in most works, containing the scientific results of explorations 
of distant countries, only new species are described, when the 
enumeration of those already known might have added invaluable 
information respecting their Geographical Distribution.” * 
The importance of every fact relating to the natural limits of 
animals and plants is felt in its bearing on the great question of 
the day — the origin of species. Whether “all the grand leading 
facts of geographical distribution are explicable on the theory 
of migration, together with subsequent modification and the mul- 
tiplication of new forms,” cannot be safely answered until we 
have more precise as well as more extensive knowledge of habi- 
tats. We should know more thoroughly the conditions which 
favor migration, as also the effect of barriers in preventing the 
spread of species, and ‘‘ the narrowest limits within which animals 
of different types may be circumscribed.” 
The following contributions are based mainly on the writer’s 
personal observations. So far as we know, no attempt has been 
made to form a synopsis of the life in the region described ; and 
it is hoped that this list may serve as the foundation of a more 
perfect work. The Valley of Quito is selected because it is a re- 
markably well-defined district, having a uniform temperate climate. 
It is nearly three hundred and fifty miles in length, stretching 
om 1° N. to 4°S., and has an average width of forty miles, being 
walled in by the grandest group of volcanic mountains in the world. 
These barriers have an average elevation of 12,000 feet above the 
sea, and are broken at few points, chiefly by the narrow gorges of 
the Santiago and Pastassa, and the sources of the Mira and 
Esmeraldos. The valley is subdivided by ridges into three basins 
— Quito, Ambato and Cuenca, having the respective altitudes of 
9500, 8000 and 7500 feet, and mean temperature of 59°, 61° and 
62°. At Quito the thermometric range in twenty-four hours is 
* Agassiz, Essay on Classification, p. 35. 
t Darwin, Origin of Species, p. 355. 
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