Alfred Bell — On the Butley Crag-pits. 455 



P.S. While I am upon the Crag formations, I shall beg leave to 

 refer to the Palseontology of two papers in the September Number of 

 the Geological Magazine by Dr. Morch, and Mr. S. V. Wood, jun. 



I. Dr. Morch's paper on the Mollusca of the Crag-formation of . 

 Iceland. 



No. 4. Natica varians. The Crag shell so named I am inclined to 

 refer to Brocchi's N. helicina,^ on the authority of the Marquis Monte- 

 rosata, to whom I submitted some Italian shells corresponding with 

 those of the Crag. It is not N. horealis of Gray, which is a high 

 Arctic form of N. Grcenlandica, and a Crag shell. (See Butley list.) 



No. 5. Natica hemiclausa, Sow., except in size, cannot be distin- 

 guished from a living Mediterranean shell, N. macilenta, Phil. 



No. 6. Natica occlusa, S. V. Wood, not Winkler. 



No. 16. Fusus Olavii, Beck., var. Spira longa, is probably the shell 

 for which I have suggested the name F. cordatus. 



No. 20. Nassa monensis, Forbes. The figure of the type shell 

 was not given, and the type specimen itself is lost. The determination 

 of the species in the English Crag rests upon Forbes's identification. 

 The Crag shell is not unlike some forms of Philippi's polymorphous 

 N. variabilis. 



Dr. Morch is in error in assigning to the English Crags the follow- 

 ing forms : Patella pellucida, Cyrtodaria siliqua, Astarte crebricosta. 

 and Modiolaria nigra. 



From the matrix of several specimens of Icelandic Crag (?) fossils 

 kindly given me by Dr. Morch, and the fact that most of the species 

 recorded in his list, which are not fossil in the English Crags, such 

 as Natica aperta, Tritonium Tottenni, T. scalariforme, Cyrtodaria 

 siliqua, etc., are Northern forms, I am inclined to refer this very 

 interesting deposit to a much later period than the age of any of our 

 English Crags. 



II. Mr. S. V. Wood, jun.. Sequence of Glacial beds. 



Nucula Cobboldice and Astarte Omalii, quoted as both extinct species. 

 The former is an inhabitant of the Japanese seas, and is described by 

 Dr. Gould (Otia. Conch, p. 175) as N. insignis. The opportunity of 

 comparing the Japanese and the Crag shells I owe to the kindness of 

 Mr. Jeffreys. 



Astarte Omalii=A. undulata, Gould, living in Massachusetts Bay, 

 etc. 



Cardita corbis is a native of N.W. America. P. P. Carpenter. 



Lastly. Does not the presence of Melampiis pyramidalis, Turritella 

 incrassata, and Nassa semistriata (or labiosa) in the Wexford drift, 

 point to an age nearer the Chillesford pre-Glacial stage than to a 

 later period. 



1 The N. helicina of Brocchi is assigned to N. catena by Mr. Jeffreys, and to N. 

 sordida by some Italian naturalists. Michelotti figures a specimen of N. inillepunctata 

 as N, helicina, and Philippi also figures another (?) species under Brocchi's name ! 



