x. CATALOGUES OF FOSSILS. 119 



In this point of view the facts which have come out by inquiry 

 are very instructive. Taking first the group of Cephalopoda, we 

 find some of the well-known species of upper lias to be continued 

 through the sands into the shelly bed above ; as Ammonites bifrons, 

 A. opalinus, A. striatulus, A. concavus ; Belemnites compressus of 

 Voltz, B. irregularis, B. tripartitus. On the other hand, several 

 conchiferous mollusks which occur with these Cephalopoda have 

 decided oolitic and not liassic affinity. Such are Hinnites abjectus, 

 Trigonia striata, Modiola Sowerbii, Pholadomya fidicula. 



Before the liassic life has come to an end the oolitic life has 

 begun ; a point of great importance in reasoning on the causes of 

 successive variation in the oceanic population, and one which will 

 come before us again on several occasions while following the course 

 of oolitic time. 



The e Cephalopoda bed,' as Dr. Wright proposes to call the cap 

 limestone of this sandy series, exists where the shells to which 

 it owes its name were specially abundant, or by some natural 

 circumstances were brought together. It is not known in the 

 valleys of the Cherwell or Evenlode, and very partially in any of 

 the branches of the Windrush, Coin, or Churn. But on the western 

 front of the Cotswold cliffs it extends from Cleeve-Cloud to Wotton- 

 under-Edge, appears on the Dorsetshire coast near Bridport, and 

 is recognized in France. 



CATALOGUES OF LIASSIC FOSSILS. 



In the following catalogues of fossils the species ascertained to 

 belong to the Rhsetic beds of Worcestershire and Gloucestershire 

 below, and the cap of sands above, are introduced, to complete the 

 view of liassic life and its connexions. Letters are employed, before 

 the names of places, to mark the stages of the occurrence of the 

 species, viz. : 



S. for the covering sands. 

 U. for the upper lias. 

 M. for the middle lias. 

 L. for the lower lias. 

 K. for the Khsetic series. 



The authorities for the names are given; but it has not been 

 thought necessary to add the special references. The titles of the 

 works of the several authors are given in an earlier page. 



