STRATA IN THE NEIGHBOURHOOD OF LONDON. JJTf 



a, fourth of its size; one smaller, the serrated edge of which 

 places it in the family of crista galli; and the third still 

 smaller, not half an inch in length, crenulated on each 

 tide of the hinge. 



J A species oi pecten. There are two or three small species 

 o/ pecten in the English chalk ; beside a shell with long 

 slender spines, which may be safely classed with the pecten. 



A crania fanomia craniolaris, Linn., crania personata, 

 'Lam.). This fossil is not known in the Englisrh chalk; nor 

 indeed could it be easily ascertained, unless the inferior 

 valve happened to be well displayed. 



Three terebratula. T. sulcata and a terebratula agreeing 

 with anomia terebratula Linn, are frequently found in our 

 chalk; and sometimes another species, hardly half an inch 

 in length, with remarkably acute and well defined ribs. 



A spirorbis. Traces of these shells are frequently found 

 on the surface of the ecldnitas. 



Ananchitce, f echinus ovatusjy the crustaceous covering 

 of which, it is remarked by Messrs. Cuvier and Brongniarr, 

 remains calcareous, and has assumed a sparry texture, while 

 the middle alone is changed into silex. No actual change * 



has however taken place, as far as respects the flinty part of 

 the fossil, the flint having merely filled up the hollow of the 

 sparry crustaceous covering. This fosiil is frequently found 

 in the English chalk. 



Porpita. These also occur in the English chalk. 



Five or six different fossil bodies called by the French 

 ory otologists polypierSf one appearing to belong to the genus 

 caryophyllaea. Several of these bodies, from the English 

 chalk, have been figured in the Org. Rem. vol. II, PI. XIll, 



fig 70 to 79. 



Another is supposed to belong to the genus miUepora. 

 This is generally brown, and is in the state of oxidized iron, 

 as resulting from the decomposition of pyrites. These fos- 

 sils exist in the Wiltshire soft chalk. 



Lastly, shark's teeth* These also occur frequently in the 

 English stratum. 



Messrs. Cuvier and Brongniart state, that there are many Many more 



more fossils in the chalk stratum of France, than t^iose p^gjj^^"j.jj*^® 



which have been just referred to. This is also the case with turn, and in 



^|jg the English. 



