INTRODUCTION. 495 



opposing coast. It seems probal)le, therefore, that (hiring the Red ('rag period tlic 

 Atlantic storms crossed East Anglia further to the south, being attended by a 

 prevalence of easterly rather than of westerly gales. ^ 



The Crag of Walton-on-Naze in the county of Esse.x contains, as just stated, 

 many Coralline (Gedgravian) Crag forms, some of them in great abundance, but 

 we find there also a fair number of species unknown or very rare at the latter 

 place, which were probably immigrants from outside regions. Of these may be 

 specially mentioned : 



*Nassa elegcms. 



*Natica catenoides. 



* 5) propinqua. 



Actason Nose. 



* „ reticosa and vars. 



Mflampus pyramidalis . 



Farpura lapiUus (Lower Crag varieties). 



^Nucula Iseviijata. 



* „ tetragona. 



Pectuncidas glycimtris, var. sabobiiqua. 



^Neptunea coiitraiia, one minute and 



^Gardiimi Parklnsoni. 



young specimen in the 



„ edjide (large and strong 



Coralline Crag of Boyton. 



variety). 



Seaiiesla costifer. *Adarte obliquata. 



Baphitoma mitrula. * Venus imbricata. 

 Enlimene pendula. Artemis exoleta. 



* „ terebellata. *Mactra arcuata. 

 Lacuna suboperta. * „ elUptica. 



*Troch'iis cineroides. Corbuloniija complanata. 



,, nod'idiferens. *Pholas crispata. 



* ,, subexcavatiis. * ,, cijlntdyrica. 



Those marked auilt a * o<-citr also in the Coralline Crag of Boijton. As before 

 stated most of the characteristic species of the Coralline Crag are found also 

 at Walton or Oakley. CI. Reid remarks that the principal interest of the Walton 

 Crag lies in the close resemblance of its fauna to that of the Coralline Crag 

 [op. cit., p. 83). 



It may be noticed that the Walton species just named are not specially 

 northern forms. The invasion of the latter had at that time hardly commenced. 

 At Little Oakley, however, a village about 5 miles to the N.N.W. of Walton, 

 there is a remarkable section, the importance of which I discovered by accident, 

 with a fauna containing nearly all the southern species of the latter place and 

 generally identical with it, but also some distinctly northern and arctic forms, 

 unknown or rare at the earlier horizon, such as — 



1 In a short paper published in 1849 (Qtiart. Journ. Geol. Soc, vol. v, p. 353) Mr. T. G. Ringler 

 Thompson expressed the opinion, though on different grounds, that a great part of the Red Crag 

 originated under the influence of easterly winds. (See also F. W. Harmer, Quart. Journ. Geol. Soc. 

 vol. Ivii, p. 407, 1901.) 



