408 PETBIFACTIONS AND THEIR TEACHINGS. CHAP. IV. 



were formed in the clay-nodule by shrinking; and if the 

 specimen be closely examined, the shells will be found split 

 across and displaced by the fissures; thus presenting an inte- 

 resting illustration of the faults, or dislocations of the strata, 

 so familiar to the geological observer. 



FOSSIL SHELLS. Table-case 18. These are chiefly from 

 tertiary deposits; many are from the eocene strata of the 

 Paris basin, at Grignon ; these are recognisable by their white- 

 ness ; those from Hordwell by their dull leaden colour ; while 

 the shells from the Crag are more or less tinted with ochre. 

 The specimens in both Cases are labelled, and named with 

 great accuracy, by the eminent conchologist, Mr. S. P. Wood- 

 ward, who has greatly increased the value and interest of this 

 department of the Gallery of Organic Remains. 



CORALS AND OTHER ZOOPHYTES. Table-case 17. Until these 

 fossils are marked and arranged, it is in vain to attempt a satis- 

 factory description. I can merely mention that there are 

 some fine specimens of corals from the Silurian rocks, and 

 others from the Coral-rag of the Oolite formation. 



FoRAMiNiFERA. 1 Of this interesting family of invertebrata, 

 whose organization and zoological relations have but very 

 recently been understood, there are specimens of some of the 

 larger forms in the Case before us; viz. of Nummulites and 

 Orbitolites. 2 Among the former, the visitor may observe 

 a block of white limestone, composed of an aggregation of a 

 species of Nummulites, of which there are detached specimens 

 affixed to cards, and labelled ; it is a fragment of the Great 

 Pyramid of Egypt, that stupendous fabric being in a great 

 measure built of nummulitic limestone. 3 



1 I would refer the reader for an account of the nature of the Forami- 

 nifera, to my " PICTORIAL ATLAS OP ORGAKIC REMAINS," p. 142, and p. 186 

 and Plates LXI. and LXII. 



2 The structure of these bodies has lately been ably elucidated by our 

 eminent physiologist, Dr. W. B. Carpenter; "On the microscopic Struc- 

 ture of Nummulites, Orbitolites, and Orbitoides." Geol. Journal for 

 1850. 



3 This specimen was formerly in my collection. See " Wonders of 

 Geology/' vol. i. p. 248. 



