XXXVi PHOCEEDINGS OF THE GEOLOGICAL SOCIETY. 



of these remains is alone regarded, and the habits of the animals of 

 which they have formed the harder parts considered to be the same 

 with those of certain animals now existing ; but when, as appears the 

 case in the localities noticed, the structure of the rocks themselves 

 would support such inferences, they become of great geological value. 

 In this way we may advance towards much knowledge of the coasts 

 and the depths of water around them at different times in various 

 parts of the earth's surface, and from the local or extended distribu- 

 tion of particular marine animals, infer the physical conditions under 

 which their remains have been entombed. 



Connected with the same communication there is a note by Mr. 

 Salter, on the fossils of the lowest Wenlock shales, east of Llandegle, 

 Builth, in which he remarks on the mixture of Caradoc and Wen- 

 lock fossils (trilobites, brachiopod shells, and a single coral) there 

 found. The absence of ordinary bivalve and univalve shells is no- 

 ticed, as also that of terebratulse, large flat orthides, corals, and tri- 

 lobites, characteristic of the Woolhope limestone. This is apparently 

 another example of the eifects of local conditions, so needful to in- 

 vestigate when we attempt generalizations as to the kind of life dis- 

 tributed over a particular area at a given geological time. 



"We find our colleague, Dr. Mantell, as indefatigable as ever in 

 developing the fauna and flora of the Wealden deposits. In his brief 

 notice of organic remains recently discovered in these accumulations, 

 he presents us with no slight additions to the list of the animal and 

 vegetable remains formerly known. He notices additional and more 

 instructive examples of Clatharia and Endogenites, and cones appa- 

 rently referable to the same species of Abies or Pinus as those found 

 in the greensand of Kent. As extending our knowledge of the 

 European flora at the time of these deposits. Dr. Mantell refers to 

 the labours of Dr. Dunker of Hesse Cassel, who has added to it no 

 less than sixty species of plants, and other species are stated to have 

 been found since Dr. Dunker's work was published*. Of the sixty 

 species of plants, thirty are referable to seven genera of ferns, and 

 twelve to Cycadese or Zamia3. 



Dr. Mantell is not aware of any new species of molluscs having 

 been discovered in the Wealden deposits of Britain, but refers to the 

 researches of Dr. Dunker for a list of 100 species found in the German 

 accumulations of the same age. Respecting crustaceans, he notices 

 the shields or cases of Cyprides and Estheria, of which four new 

 species have been detected in Germany. For the insects. Dr. Man- 

 tell refers to the labours of the Rev. P. B. Brodie, and corroborates 

 the occurrence of insects in the freshwater beds above the oolite in 

 Buckinghamshire. 



Under the head of fishes, the German accumulations of this age 

 are stated to have yielded one species of Enchodus, two new species 

 of Hybodus, two of Lepidotus, one of Sphoerodus, and one of Gy- 

 rodus. Fine specimens of the previously well-known species of 

 British Lepidotus are mentioned as having been discovered near 

 Hastings. 



* Monographic der Norddeutschen Wealdenbildung. 



