92 Lieutenant Maury on the Clouds and 



Admitting to the fullest extent the effect or causes that may be 

 supposed to have occasioned the absence of mammalian remains in 

 the secondary deposits, yet the immense preponderance of the rep- 

 tile tribes is unquestionable. Some authors have attempted to 

 account for this anomaly by assuming that antecedently to the 

 Eocene period, our planet was not adapted for the existence of mam- 

 malia, in consequence of its atmosphere being too impure to support 

 higher types of animal organisation than the cold-blooded vertebrata. 

 But the certainty that some forms of marsupial and placental mam- 

 malia inhabited the countries of the Megalosaurus and Pterodactyle, 

 — that birds in all probability existed with the Iguanodon, — and the 

 fact that insects and mollusca, and trees and plants, which now in- 

 habit regions abounding in birds and mammalia, flourished during 

 the " Age of Reptiles,'' demonstrate that the physical conditions 

 of the earth, and the constitution of the atmosphere and of the 

 waters, differed in no essential respect from those which now prevail, 

 and that the laws which govern the organic and inorganic kingdoms 

 of nature have undergone no change. 



That the class Keptilia was developed during the periods embraced 

 in this discourse, to an extent far beyond what has since taken place, 

 appears to be indisputable ; nor can any satisfactory solution of the 

 problem be offered from the data hitherto obtained. Future disco- 

 veries may however shew that coeval with the country of the Iguano- 

 don there were regions tenanted by birds and mammalia; and that 

 the almost exclusively reptilian fauna of the lands whose zoological 

 and botanical characters have formed the subject of this lecture, 

 was but an exaggerated condition of that state of the animal kingdom 

 which is exhibited by the present fauna of the Galapagos Islands.* 



On the Clouds and Equatorial Cloud Rings of the Earth.\ 

 By Lieut. Maury, of the National Observatory. 



Sailors have opportunities of making observations on clouds, and 

 the various phenomena accompanying them, which no other class 

 enjoy. The sailor, bound in his ship to the southern hemisphere, 

 enters the region of the north-east trade-winds, and frequently 

 finds the sky mottled with clouds, but generally clear ; continuing 

 his course south, he observes his thermometer to rise as he ap- 

 proaches the equator, until entering the equatorial region, he finds 

 the weather to become murky, close, and oppressive. He then 

 enters the south-east trades ; and on looking at his log-book, he is 



* See " Wonders of Geology. " Sixth Edition, p. 893. 



t The ahove is an abstract of a paper read at the meeting of Die American 

 Association, Albany, by Lieutenant Maury. 



