83 



perior bed of soft shale (a) is characterized by Ammonites striatulus, 

 A. communis, A.crassus, and Trigonia literata ; the middle portion, 

 from which alum is manufactured, by Ammonites Walcottii, A. he- 

 terophyllus, and Nautilus astacoides ; and the lowest by Ammonites 

 exaratus, A. elegans, Nucula ovum, and the remains of saurians. The 

 hard shale (Z») is distinguished by the presence of jet, Ammonites 

 elegans, Belemnites compressus , B. tuhularis, and Inoceramus dubius; 

 and the lower bed of soft shale (c) by the great abundance of Am- 

 monites annulattis. 



The marlstone, or second division of the lias series, is characterized 

 by Ammonites Hawkerensis, A. Clevelandicus, A. Stokesii, Belemnites 

 conicus, B. elongalus. Turbo undulatus, Dentalium giganteum, Iso- 

 cardia lineata, Cardigan multicostatum, C. truncatum, Corbula car~ 

 dioides, Amphidesma recurvum, Mya V-scripta, M. literata, Pla- 

 giostoma Iceviusculum , Pecten equivalvis, P.sublcevis, Avicula incequi- 

 valvis, A.cygnipes, Plicatula spinosn, Modiola scalprum, M. Hillana, 

 and Terebratula bidens, T. subrotunda, T. tetrahedra, and T. tri- 

 plirata. 



The lower lias rock is distinguished by Ammonites planicosta, Pli- 

 catula spinosa, Hippopodium ponder osum, Lutraria ambigua, Pinna 

 folium, Gryphcea depressa, G. Maccullochii, G. incurva, Pentacri- 

 nites Briareus, and P. vulgaris. 



In preparing these lists, the author says that he has omitted to 

 mention those fossils which he has not seen, or those which, from 

 their rarity, can be of little use in distinguishing the different sub- 

 divisions of theJias series ; and in conclusion, he states, that he has 

 found the fossils enumerated above, almost invariably in the beds to 

 which he has assigned them ; and he is of opinion that similar 

 sections may be drawn up on the same minute scale of the contents 

 of all the other strata, but that it remains for further investigation 

 to determine to what extent. 



A paper was afterwards read, entitled, " Observations on the 

 Loamy Deposit called Loess in the Valley of the Rhine," by C. 

 Lyell, Esq., For, Sec. G.S. 



In this paper Mr. Lyell details some observations made by him 

 in the summer of 1833, on the loess between Cologne and Heidel- 

 berg, and in several parts of Baden, Darmstadt, Wiirtemberg and 

 Nassau. Near Bonn large deposits of loess containing recent 

 shells rest on the gravel of the plain of the Rhine. The author 

 collected two hundred and seventeen entire shells, of which one 

 hundred and eighty-five individuals were of terrestrial species be- 

 longing to the genera Helix, Pupa, and Clausilia, and thirty-two of 

 aquatic species of the genera Limnea, Paludina and Planorbis. This 

 large proportion of land shells is very general in the formation. 

 The author then made a collection of such shells as are now drifted 

 down by the Rhine and occasionally cast ashore by the waves, in 

 which case the shells for the most part retain their colour and are 

 perfectly distinguishable from fossils washed out of the loess. Out 

 of two hundred and seventy-three individuals thus procured, one 

 hundred and forty-seven were land shells and one hundred and 



