ANNIVERSARY ADDRESS OF THE PRESIDENT. xliu 



pear desirable to obtain more information respecting the distribution 

 of fossil plants at different geological times than we now possess, 

 before we conclude that we have evidence enough to speak of the 

 characteristic plants of different geological epochs with the confidence 

 sometimes used. It would appear very desirable, under present in- 

 formation, to regard the subject more locally and always with refer- 

 ence to the probable physical conditions under which the plants may 

 hav^e been entombed. 



In his communication on the Silurian slates and coal of the neigh- 

 bourhood of Oporto, Mr. Sharpe gives descriptions of Isoteliis 

 Poivisii ?, lUcEnus Lusitanicus (n. s.), Orthis Noctilio {ii. s.), Orthis 

 Miniensis {n. 5.), Orthis Duriensis (n. s.), Orthis Lusita?iica (n. s.), 

 Orthoceras remotum (Salter MS.), and Belleropho7i Buriensis (n. 5.), 

 all found in those beds. 



To Professor Owen we are indebted for a description of saurian 

 remains discovered by Professor Henry Rogers in a greensand deposit 

 of the United States, considered referable to the age of part of the 

 cretaceous accumulations of Europe. The specimens placed before 

 Professor Owen enabled him to add some facts to the osteology of 

 the Mosasaurus, and to discover some species of saurians, especially 

 of the procoelian form of crocodile, not previously known in strata 

 older than the tertiary deposits termed eocene. After very import- 

 ant osteological details respecting the Mosasaurus, which require to 

 be studied in the memoir itself in order fully to appreciate the labours 

 of our colleague upon this subject, he states that, considering certain 

 of the bones to belong to the Mosasaurus, "they indicate the extre- 

 mities of that great saurian to have been organized according to the 

 type of the existing Lacertia, and not of the Enaliosauria or marine 

 lizards," and adds, "two species, at least, of true Lacertia have left 

 their remains in our English chalk." 



Professor Owen next notices some remains of a procoelian reptile, 

 and proposes to indicate the saurian, and probably mosasauroid 

 genus to which it belongs by the name of Macrosaurus. Upon 

 other remains he estabhshes the genus Hyjwsaurus, an Amphicoehan 

 crocodile, and then notices specimens from the same localities laid 

 before him by Professor Henry Rogers, which he remarks are " the 

 first evidences of the genus oi the modern Crocodilus or Alligator 

 that have been discovered in strata older than the eocene tertiary." 



The accumulations amid which these saurians have been de- 

 tected are inferred, from the marine remains found in them, to be of 

 the same age as part of the cretaceous series of Western Europe, 

 similar marine molluscs having been considered to exist and to have 

 been entombed in mineral matter at the same geological period in 

 the seas surrounding the shores of land in the areas now occupied by 

 the United States and Western Europe. The remains described by 

 Professor Owen thus possess not only high interest as additions to the 

 forms of life which have existed at different times on our earth, but 

 also as showing the co-existence of certain saurian and molluscous 

 forms at equal geological times. We have thus the modern croco- 

 dile or alligator (living probably much in the same way as the spe- 



